Geography of United States

Geography of United States

United States of America is a country consisting of 50 states, a federal district, and various outlying areas. Forty-nine of the states and the federal district (the District of Columbia) are in North America. The 50th state, Hawaii, is an island group in the Pacific Ocean. The outlying areas are in the Pacific Ocean and the Caribbean area, and include American Samoa, Guam, Northern Marianas, Puerto Rico, and Virgin Islands. This article is concerned with the United States proper—the 50 states and the District of Columbia. .

The United States is commonly called America and its people Americans. More properly, however, America applies to the entire Western Hemisphere, and Americans to all people who live there.

The United States is one of the largest and most powerful countries in the world. It is exceeded in size only by Russia, Canada, and China. Only China and India have larger populations. The United States leads the world in agricultural and industrial production and is one of the world's richest countries in mineral resources.

The nickname "Uncle Sam" is often used to refer to the United States or its government. In other countries United States citizens are often called Yankees or Yanks. (Within the United States the term Yankee applies only to Northerners, especially New Englanders.) The national bird is the bald eagle. The rose is the national flower.

Geography of the United States

Until 1959, when the territories of Alaska and Hawaii became the 49th and 50th states, the 48 contiguous (adjoining) states and the District of Columbia were known as the continental United States. These states are bounded on the north by Canada, on the east by the Atlantic Ocean, on the south by the Gulf of Mexico and the Republic of Mexico, and on the west by the Pacific Ocean. Alaska is separated from the main part of the country by more than 500 miles (800 km) of Canadian territory. Hawaii, a chain of volcanic and coral islands, lies about 2,400 miles (3,900 km) southwest of California in the Pacific Ocean.

With the addition of Alaska and Hawaii, the United States replaced Brazil as the world's fourth largest country. The northernmost point of the United States is Point Barrow, Alaska, 1,300 miles (2,100 km) from the North Pole; the southernmost point is Kalae (South Cape), Hawaii Island, Hawaii, at about the same latitude as Mexico City. The point farthest east is West Quoddy Head, Maine. The westernmost point, Attu Island, Alaska, is in the Eastern Hemisphere south of Siberia. The geographic center of the United States, excluding Hawaii, is in Butte County, South Dakota, 14 miles (23 km) east of where the Wyoming, South Dakota, and Montana borders meet.

From Hawaii to eastern Maine measures 5,100 miles (8,200 km); from Point Barrow to Florida's southern tip, 4,300 miles (6,900 km). The greatest east-west distance in the 48 contiguous states is 2,800 miles (4,500 km); the greatest north-south, 1,650 miles (2,660 km). The border with Canada totals 5,527 miles (8,895 km), including 1,540 miles (2,478 km) in Alaska. The Mexican border is 2,013 miles (3,240 km) long.

The United States coastline totals 12,383 miles (19,929 km), of which Alaska has 6,640 miles (10,686 km) and Hawaii 750 miles (1,207 km).

The United States contains a wide range of landforms, from lofty mountains to flat, arid deserts and vast, grassy plains. There are old mountain systems, rounded by the action of erosion; and young mountain ranges, still tall and jagged. The northern part of the country bears the scars of huge glaciers that covered the land during the last Ice Age. In some areas, especially Alaska, glaciers are still active. There are also active and dormant volcanoes, vast plateaus and basins, deep canyons, gorges, and valleys. Some of the lakes and rivers of the United States are among the world's largest.

The following text, describing the major physical regions of the United States, deals primarily with the 48 contiguous states. The physical features of Alaska and Hawaii are discussed fully in separate articles.

The Atlantic and Gulf Coastal Plain extends along the Atlantic and Gulf coasts from Cape Cod, Massachusetts, to Mexico. The plain was formed millions of years ago when deep marine sediments were deposited on the ocean's floor. Eventually these sediments emerged to become dry land. This flat coastal lowland varies in width from only a few miles in New England to more than 500 miles (800 km) in the lower Mississippi River valley. Sandy beaches, bars, and islands border the coast; swamps and marshes are often found short distances inland.

The inner margin of the Atlantic Coastal Plain is marked in part by the fall line, where rivers descend from the Piedmont Plateau, forming rapids and waterfalls. Washington, D.C., Richmond, Virginia, Columbia, South Carolina, and many other southeastern cities are located on or near the fall line.

The Appalachian Highlands is a region of mountains, valleys, and plateaus extending southwestward from New England to Alabama. The Appalachians are one of the oldest mountain systems in the country. Through the ages they have been worn down relatively low. The region is divided into five sections—New England, the Piedmont Plateau, the Blue Ridge, the Ridge and Valley, and the Appalachian Plateau:

New England is largely an area of low, rounded mountains. Peaks rising to more than 4,000 feet (1,200 m) above sea level are found mainly in the Green Mountains of Vermont and the White Mountains of New Hampshire.

The Piedmont Plateau or Piedmont, stretching from the mouth of the Hudson River to Alabama, is a hilly plateau section bordering the Atlantic Coastal Plain.

The Blue Ridge section rises sharply from the Piedmont Plateau, from Pennsylvania to Georgia. This mountainous section includes the Great Smoky, Blue Ridge, and Black Mountains. Mount Mitchell, a 6,684-foot (2,037-m) peak in North Carolina's Black Mountains, is the highest point in the East.

The Ridge and Valley section west of the Blue Ridge section, is made up of many steep-sided ridges running from New York to Alabama. Except for the broad Great Valley, which continues on into Canada, the valleys separating the ridges are short and narrow.

The Appalachian Plateau in the westernmost part of the highland region, is cut by many deep river valleys and has a mountainous appearance. Parts of this plateau include the Catskill Mountains in New York; the Allegheny Plateau, largely in Pennsylvania and West Virginia; and the Cumberland Plateau, mainly in Kentucky and Tennessee.

The Interior Plains, the largest physical region in the United States, are located west of the Appalachian Highlands, east of the Rocky Mountains, and north of the Gulf Coastal Plain. The region's greatest dimensions are about 1,200 miles (1,900 km) east-west and 1,300 miles (2,100 km) north-south. Thick beds of sedimentary rocks underlie this vast plains area. North of the Missouri and Ohio rivers are deep glacial deposits.

At about the 100th meridian, the Interior Plains divide into the Great Plains, to the west, and the Central Lowlands, to the east. Both sections have vast stretches of flat land and of gently rolling land. A major difference between the two areas is elevation—the Great Plains lie at an elevation of 2,000 to 6,000 feet (600 to 1,800 m), the Central Lowlands are much lower.

The Interior Plains are bordered by two upland regions—the Superior Uplands on the north, and the Central Uplands on the south.

The Superior Uplands are in Minnesota, Wisconsin, and, Michigan. They are part of the huge Canadian Shield and rise to a maximum height of about 2,000 feet (600 m).

The Central Uplands are in Missouri, Arkansas, and Oklahoma. They include the Ozark Plateau and the Boston and the Ouachita Mountains. The Ozarks rise to about 2,500 feet (760 m); the Ouachitas, to 3,000 feet (900 m).

The Rocky Mountains rise abruptly from the Great Plains and extend northwesterly from northern New Mexico to Canada. Compared with the Appalachians, the Rockies are geologically young and are considerably more rugged. Within the Rockies are scores of ranges, many of which are separated by broad valleys and basins. The Wyoming Basin, in Wyoming, Colorado and Utah, is the largest of the mountain basins and divides the Rocky Mountains into northern and southern branches.

Among the many high ranges in the Southern Rockies are the Front, Park, and Sawatch ranges, in Colorado. Those in the Northern Rockies include the Bighorn Mountains and the Teton Range, in Wyoming; the Uinta Mountains and the Wasatch Range, in Utah; the Lost River Range, in Idaho; and the Bitterroot Range, on the Idaho-Montana border. On the whole, the Northern Rockies decline in height toward the north, while the Southern Rockies become lower toward the south.

The highest of the Rocky Mountain peaks are Mounts Elbert, Massive, and Harvard, in Colorado—all extend more than 14,400 feet (4,390 m) above sea level. Although not as high, Colorado's Pikes Peak (14,110 feet [4,301 m]) is more famous.

The Pacific Coast extends from Canada to Mexico along the Pacific Ocean and is composed chiefly of high mountain ranges and intervening fertile valleys. Bordering the coast, from northern Washington to southern California, are the Coast Ranges. They include Washington's Olympic Mountains, Oregon's Coast Range, the Klamath Mountains on the Oregon-California border, and numerous low ranges in California. Altitudes vary from about 2,000 feet (600 m) in the Coast Range to 9,000 feet (2,700 m) in the Klamath Mountains. In many areas the rugged coast is marked by steep cliffs and rocky headlands.

East of the Coast Ranges are the Cascade Range of Washington and Oregon, and the high Sierra Nevada of California. Lofty volcanic peaks dot the Cascades, towering high above the other mountains. Mount Rainier, the highest of these old volcanoes, rises 14,410 feet (4,392 m) above sea level. The rugged Sierra Nevada range includes Mount Whitney, which rises 14,494 feet (4,418 m) and is the highest peak in the United States outside of Alaska (Mount McKinley, in the Alaska Range, rises to 20,320 feet [6,194 m]). In Death Valley, less than 100 miles (160 km) southwest of Mount Whitney, is the lowest point in the country—282 feet (86 m) below sea level.

Within the Pacific Coast region are two large lowlands, almost completely enclosed by mountains. One is the Puget Sound-Willamette Valley, in western Washington and Oregon; the other, the Central Valley of California.

The Intermountain Region, lying between the Rocky Mountains and the Pacific Coast region, is a vast semiarid and arid land. Among its many and colorful landforms are mountains, plateaus, buttes, mesas, gorges and canyons, salt lakes, and deserts. There are three main sections of the Intermountain region—the Colorado Plateau, the Basin and Range section, and the Columbia Plateau:

The Colorado Plateau is in the southeast. It covers parts of Colorado, Utah, Arizona, and New Mexico, and varies in elevation from 5,000 to 11,000 feet (1,500 to 3,350 m). Many deep gorges cut the plateau, the Grand Canyon of the Colorado River being the largest and deepest.

The Basin and Range section, covering parts of Utah, Nevada, California, Arizona, New Mexico, and Texas, is a vast dry area of low mountains, most of them running north and south, and broad basins. Some of the ranges attain heights of 10,000 feet (3,000 m), but most are lower. The northern part of the Basin and Range, mainly in western Utah and Nevada, is occupied by the Great Basin. It is completely surrounded by higher land, and the waters that drain into it either evaporate or flow into salt lakes.

The Columbia Plateau in parts of Washington, Oregon, and Idaho, is a flat expanse of thick volcanic lava. Here the Columbia and Snake rivers have cut deep canyons and gorges.

The Continental Divide, in most areas, follows the crest of the Rocky Mountains. Rivers east of the divide drain into the Atlantic Ocean, the Gulf of Mexico, or Hudson Bay. Those to the west drain into the Gulf of California, the Pacific Ocean, or the Great Basin, which has no outlet to the sea.

The Atlantic Ocean receives the water of the Great Lakes, the St. Lawrence River, and the many rivers east of the Appalachian Highlands. The St. Lawrence River is the largest river on the east coast, but most of its course is in Canada. Other eastern rivers are much shorter than the St. Lawrence but are nevertheless of great value, especially for purposes of navigation and for the harbors formed by their mouths. These rivers include the Penobscot, Kennebec, Merrimack, Connecticut, Hudson, Delaware, Potomac, James, Roanoke, Santee, Savannah, and Altamaha.

Most of the rivers between the Appalachian and Rocky Mountains are part of the Mississippi River system, which drains into the Gulf of Mexico. Chief tributaries of the Mississippi include the Ohio, Missouri, Arkansas, and Red rivers. Other rivers in the Mississippi basin are the Wisconsin, Illinois, Wabash, Allegheny, Monongahela, Kanawha, Kentucky, Cumberland, and Tennessee rivers, to the east of the Mississippi River; and the Yellowstone, Cheyenne, Platte, Cimarron, and Canadian rivers, to the west.

River improvements in the Mississippi basin have been chiefly for navigation, flood control, recreation, and conservation. On some rivers, however, such as the Tennessee, Cumberland, and Missouri, much water power has been developed.

Except for tributaries of the Mississippi, rivers on the Gulf Coastal Plain flow directly into the Gulf of Mexico. From east to west, these rivers include the Apalachicola-Chattahoochee, Mobile-Alabama-Coosa, Tombigbee, Pearl, Sabine, Trinity, Brazos, and Rio Grande.

The Red River of the North and its tributaries in Minnesota and North Dakota are the most important streams that flow northward to Hudson Bay.

West of the Rockies, many rivers descend from the high mountains and plateaus. There are, however, few large streams except for the Yukon, Kuskokwim, Columbia, Snake, and Clark Fork rivers, in the north; the Colorado, Green, and Gila rivers, in the south; and the Sacramento and San Joaquin rivers, in the Central Valley of California. Of these, the Colorado flows into the Gulf of California, and the rest empty into the Pacific Ocean. Rivers flowing into the Great Basin have no outlet to the sea; the Humboldt River, in Nevada, is the largest of these. Western rivers are used widely for irrigation and water power.

The Great Lakes—Superior, Huron, Michigan, Erie, and Ontario—are the largest lakes of the United States. Of the five, only Lake Michigan lies entirely within the United States. The rest are shared with Canada. A total of 60,440 square miles (156,540 km2) of the Great Lakes is part of the United States.

Smaller lakes abound in several sections. In the North, the land from Minnesota to New England is dotted with thousands of lakes that were formed during the time glaciers covered the land. The largest of these is the Lake of the Woods, in Minnesota and Canada.

In the dry regions of the West are many salt lakes, of which the Great Salt Lake, in Utah, is the largest. Smaller salt lakes include the Salton Sea, in California, and Pyramid Lake, in Nevada. High in the western mountains are some of the nation's most scenic lakes. Among them are Lake Tahoe, in California and Nevada; Crater Lake, in Oregon; and Yellowstone and Jackson lakes, in Wyoming.

Of the many lakes and lagoons in the Gulf Coast area, Lake Pontchartrain, in Louisiana, and Lake Okeechobee, in Florida, are the largest.

The climates of the United States vary greatly from section to section. Temperatures have reached such extremes as — 80° F. (-62° C.) in Alaska and 134° F. (57° C.) in California. Annual rainfall also varies widely—from a record high of 460 inches (11,680 mm) in central Kauai, Hawaii, to an annual average of less than 2 inches (50 mm) in the deserts of the Southwest.

On the whole, the interior of the country experiences the greatest seasonal change in temperature. It heats quickly in summer and cools rapidly in winter. In some coastal areas, because of the influence of offshore ocean currents, there is relatively little change throughout the year.

Except for Alaska and Hawaii, the United States is situated in the middle latitudes—the so-called temperate zone. Here, cold polar air masses from the north meet warm subtropical air masses from the south. The meeting of these masses of air produces cyclonic storms, which are carried eastward across the country by the prevailing westerly winds. Most of the nation's rain and snow occurs in conjunction with cyclonic storms.

The following broad types of climate are found:

ranging from the Dakotas, Nebraska, Kansas, and Oklahoma eastward to the Atlantic Ocean. Within this region, there are two phases of the climate—a northern and a southern phase. The northern phase occurs in the northernmost states from the Dakotas to Maine. Summers are short and cool; winters are long, snowy, and severely cold. Temperatures in Duluth, Minnesota, for example, average 39° F. (4° C.) annually, 9° F. (-13° C.) in January, and 66° F. (19° C.) in July. Annual precipitation averages 30 inches (760 mm); snowfall, 78 inches (1,980 mm). (Precipitation figures include melted snow and ice pellets.)

The southern phase is characterized by long, hot summers and short, cold winters. For example, temperatures in St. Louis, Missouri, average 56° F. (13° C.) annually, 31° F. (-1° C.) in January, and 79° F. (26° C.) in July. Yearly precipitation averages 36 inches (910 mm); snowfall, 19 inches (480 mm).

extending from eastern Texas to the Atlantic Coast. As a whole, the region receives the largest amount of rainfall in the country, from 40 to 60 inches (1,000 to 1,500 mm) annually. Summers are long and hot; winters are short and mild. In Jackson, Mississippi, for example, temperatures average 65° F. (18° C.) annually, 47° F. (8° C.) in January, and 82° F. (28° C.) in July. Average yearly rainfall is 49 inches (1,240 mm); snowfall, about 1 inch (25 mm).

found on the southern tip of Florida and in Hawaii. Warm weather prevails throughout the year; rainfall is abundant; and snow is unknown. Temperatures in Miami, for example, average 75° F. (24° C.) annually, 67° F. (19° C.) in January, and 82° F. (28° C.) in July. There is normally about 60 inches (1,520 mm) of rain yearly. Honolulu has somewhat warmer winters than Miami, milder summers, and less rainfall.

found in central and southern California. As implied by the name, this type of climate is similar to that of regions bordering the Mediterranean Sea. The climate is marked by scant rainfall; long, hot, dry summers; and short, mild, rainy winters. Snow and freezing weather are infrequent. For example, temperatures in downtown Los Angeles average 65° F. (18° C.) annually, 57° F. (13° C.) in January and 73° F. (23° C.) in July. Annual rainfall is about 14 inches (360 mm).

extending along the Pacific Coast from northern California to the Canadian border. Because of the protection provided by the Cascade Range and the tempering influence of the Pacific Ocean, the climate varies little throughout the year. Winters are mild and summers are cool. In Seattle, Washington, for example, temperatures average 52° F. (11° C.) annually, 40° F. (4° C.) in January and 66° F. (19° C.) in July. Annual precipitation averages about 36 inches (910 mm); snowfall, about 8 inches (200 mm). A slightly cooler version of this climate, with considerably more rainfall, is found along Alaska's southeastern coast.

predominating over the Great Plains and most of the Intermountain region. Rainfall, scant and unreliable throughout this zone, decreases toward the southwest, where deserts are found in parts of Nevada, Utah, California, and Arizona. Throughout the region, summers can be very hot and winters extremely cold. Winters in the northern section are particularly long, cold, and snowy. In Great Falls, Montana, for example, temperatures average 45° F. (7° C.) annually, 21° F. (-6° C.) in January, and 69° F. (21° C.) in July. Annual precipitation averages about 15 inches (380 mm); snowfall, about 58 inches (1,470 mm).

found in southwestern Arizona and southeastern California. The climate is marked by extreme dryness; an abundance of sunshine; long, hot summers; and warm winters. For example, Phoenix, Arizona, averages 70° F. (21° C.) annually, 91° F. (33° C.) in July, and 51° F. (11° C.) in January. Annual rainfall averages about 7 inches (180 mm).

found in the interior of Alaska and along the Bering Sea and Arctic Ocean coasts. Winters are severely cold, averaging -12° F. (-24° C.) in Fairbanks and -16° F. (-27° C.) in Barrow in January. July temperatures average 61° F. (16° C.) at Fairbanks and 39° F. (4° C.) at Barrow. There is considerable snow, but limited annual precipitation in general.

Native Plants and Animals

With extremes of climate ranging from arctic to tropical, and with landforms that include mountains, plains, deserts, and swamps, the United States has a rich variety of plant life.

Forests. When Europeans first came to North America, forest covered almost all the area now included in the United States east of the Mississippi River. Prairies and other grasslands extended westward from the Mississippi to the Rockies, where forests began again. The clearing of land for farming and unrestricted lumbering destroyed many of the forests, especially in the Midwest and East.

Today, Alaska has the greatest forested area in the United States, followed by California and Oregon. Extensive forests are also found in the South and in the Northeast and in the Great Lakes states.

Coniferous, or cone-bearing, trees grow mainly in the Northeast, in the Rocky Mountain region, on the Pacific Coast, in Alaska, and in the South. Fir, spruce, and red and white pines are among the most common trees in the Northeast. Engelmann spruce, ponderosa pine, western white pine, lodgepole pine, and Douglas fir are among the chief trees in the Rockies. On the Pacific Coast are Douglas fir, ponderosa pine, sugar pine, red cedar, and Sitka spruce. The giant redwoods grow in California.

Hemlock and Sitka spruce form dense forests on the southeast coast of Alaska. There are forests of white spruce mixed with broadleaf trees such as white birch and aspen in the interior of Alaska. A region of mostly coniferous trees, including longleaf. shortleaf, and loblolly pines, extends from North Carolina to Texas. Bald cypress grows in swamps in the South.

Broadleaf trees are most abundant in the Midwest. These broadleaf trees include oak, elm, maple, beech, hickory, walnut, ash, and birch. Tupelo, red gum, and magnolia are broadleaf trees common in the South. Certain types of palms and other tropical trees grow in the Everglades and in Hawaii.

Grasslands occupy the area between the eastern forests and the Rocky Mountains. In the eastern part of this grassland area is the tall-grass prairie, which contains such grasses as big bluestem, Indian grass, and prairie cordgrass. Cities and farms now occupy most of the region.

West of the prairie, roughly west of the 100th meridian, lies the short-grass country of the Great Plains. Here grow buffalo grass, side oats grama, western wheatgrass, and other short and medium grasses.

More than 20,000 species of flowering plants are native to the United States, and numerous species introduced from Europe and Asia are now as much a part of the American scene as the native plants. The goldenrod is perhaps the most widespread flower in the United States; it grows in all states except Hawaii.

In the East, the earliest wildflowers to bloom in the spring are woodland plants such as hepaticas, trilliums, bloodroot, and spring beauty. Typical of the Great Plains are sunflowers, blazing stars, pasqueflowers, and lupines. Texas is noted for the bluebonnet and Indian paintbrush.

Bitterroot, harebells, Rocky Mountain columbine, and other hardy plants grow in the Rockies. The numerous desert wildflowers include cacti, yuccas, mariposa lilies, and the desert star. Along the Pacific Coast grow such colorful flowers as poppies and godetias.

Alaska has a rich variety of wildflowers, including harebells, lupines, violets, and hyacinths. Tropical flowers such as hibiscuses, orchids, and the maile, prized for making leis, grow in Hawaii.

Among the common plants introduced from Europe are the dandelions, bouncing bet, yellow iris, and Queen Anne's lace. The tiger lily came from Asia, and the daylilies come from Eurasia.

For various state flowers, see articles on the states.

Desert areas exist chiefly in Arizona, California, Nevada, and Utah. Sagebrush, greasewood, creosote bush, agaves, yuccas, and cacti are typical plants of the deserts. The giant saguaro cactus and the Joshua tree, a yucca, are the largest desert plants.

Such evergreen shrubs as scrub oak, chamise, and manzanita grow in the chaparral of southern California where there is a Mediterranean-type climate. Mesquite is a thorny shrub or small tree that grows in thorn scrub, semiarid areas in the southwest. Mosses, lichens, and short grasses are characteristic of the arctic tundra, in Alaska, and the alpine tundra, in the Rockies.

The United States has a great variety of animal life, although some once-common animals are extinct and others survive only under government protection. A few wild animals, such as the white-tailed deer, are more abundant than they were in colonial times.

Free-ranging bison exist only in preserves, and the musk ox is found in Alaska only because it was reintroduced after it had been exterminated there. Black bears, brown bears (including grizzly bears), and polar bears are the largest carnivores (meateating animals) of the United States. Members of the deer family native to the United States are the white-tailed deer, mule deer, moose, caribou, and American elk.

Members of the dog family include gray and red wolves; red, gray, and arctic foxes; and the coyote. Cat-family members include the mountain lion, bobcat, and lynx. Jaguars and ocelots are sometimes found in the Southwest. Jackrabbits, cottontail rabbits, and snowshoe rabbits are numerous. Among native rodents are beavers, muskrats, porcupines, squirrels, ground squirrels, marmots, and prairie dogs.

There are several native species of weasels and other members of the weasel family, including the marten, fisher, mink, skunk, badger, and wolverine. The raccoon is widely distributed. The opossum is the only marsupial (pouched mammal) found in the United States.

Many kinds of ducks, geese, and other waterfowl are found in the United States. Shorebirds such as plovers, sanderlings, and sandpipers also are numerous. Among native ground birds are the turkey, quail, prairie chicken, and grouse.

Native wading birds include herons, ibises, and egrets. Among birds of prey are numerous species of hawks and owls and the golden and bald eagles. The buzzard and the California condor are native carrion-feeding birds. Among the hundreds of kinds of songbirds are thrushes (including robins), warblers, cardinals, tanagers, sparrows, and bobolinks.

Alligators and crocodiles are found in Florida. Among the many kinds of turtles are the snapping turtles, the alligator snappers, box turtles, and desert tortoises. Rattlesnakes are found in almost all of the states, but chiefly in the Southwest. Other poisonous snakes include the water moccain in, found in the Southeast and coral snakes, found in the Gulf Coast states and in the Southwest. The many kinds of nonpoisonous snakes include bull snakes, hognose snakes, king snakes, and garter snakes. Lizards are most numerous in the Southwest. The Gila monster, a venomous lizard, lives chiefly in deserts of the Southwest.

About 60 different species of frogs and toads and 80 species of salamanders are native to the United States. The bullfrog, largest of the native frogs, is found in the eastern and central United States.

Sunfish and their relatives, the basses, are found almost everywhere east of the Rockies. Brook, rainbow, cutthroat, and Dolly Varden are among native trout species. Muskellunge, northern pike, and walleyed pike are most numerous in the Northeast.

The Economy of the United States

Manufacturing is the single most important sector of the American economy. It employs roughly a fifth of the nation's labor force and produces about a fifth of the gross domestic product. The United States produces an enormous range of both consumer and industrial goods. No other country equals it in total production and consumption of manufactured items.

By most indicators of industrial strength, such as the production of steel, cement, and chemicals, the United States ranks among the world's top producing nations. Advanced technology has contributed heavily to the United States' preeminent position, especially since the early 1900's. In the late 1990s the United States lead a number of advanced technology fields, such as pharmaceuticals, biotechnology, and aerospace.

The Midwest and the South are the chief manufacturing regions, each contributing about one-third of the nation's output, in terms of value added by manufacture; the Northeast contributes almost one-fourth, and the West accounts for the remainder. California, New York, Ohio, Texas, Illinois, and Michigan are the leading manufacturing states.

A growing trend among many American companies, especially since the early 1980's, has been to move manufacturing and assembling operations to foreign countries, where labor is cheaper. From there finished goods are shipped back to the United States or to other destinations.

The chief manufactured products, by groups, are transportation equipment, foods, chemicals, machinery, electrical and electronic equipment, printed materials, fabricated metal products, instruments, paper and paper products, and primary metals. (These groupings are based on those used by the U.S. Department of Commerce in its periodic Survey of Manufactures and are somewhat arbitrary.)

The manufacturing of automobiles, trucks, recreational vehicles, and related parts and equipment is the nation's leader in terms of value added by manufacture. It centers in the Great Lakes area, especially in Detroit and other cities of southeastern Michigan. There are also large assembly plants elsewhere, especially in other parts of the Midwest and in California.

The production of aerospace equipment, including airplanes and space vehicles, is a considerably smaller industry by value and employment than that of motor vehicles. Major centers of production are on the Pacific Coast, mainly in or near Seattle and Los Angeles.

America's shipbuilding industry is small and unable to compete on a cost basis with large foreign builders. It survives at a number of coastal locations, from Maine to California, largely because of federal expenditures for naval vessels.

Feeding America's huge population requires a giant food-processing industry. Some foods, such as dairy products, are processed in all parts of the country; others, such as meat, fruit, and vegetables, are processed mainly in major producing areas. Meat processing and packing is done mainly in the Midwest and in Texas and California. The canning and freezing industry is largest on the Atlantic Coast, in the Great Lakes states, and on the Pacific Coast.

Chemical manufacturing yields such products as industrial chemicals, drugs, plastics, and soaps and cleaners. Production takes place in many parts of the nation, but is most heavily concentrated in the Northeast, especially in New York, New Jersey, and Pennsylvania, and in Illinois, Ohio, and Michigan. Large chemical plants are also located along the Texas and Louisiana coast and in California.

The machinery group, the nation's leader until the early 1980's, consists primarily of machines for farms, mines, construction, factories, offices, and homes. Electronic computers and related equipment make up the most valuable single category in this group. The Northeast and the Great Lakes states lead in the production of most kinds of machinery. California, Massachusetts, New York, and Minnesota are the principal states in the manufacturing of electronic computing equipment.

Manufactured goods in this group include home appliances; electric lighting equipment; transformers; motors; generators; and radio, television, telephone, and other communications equipment. The manufacturing of these and related products is done mostly in the Northeast and in the Midwest. However, the making of electronic components, chief of which are semiconductors, centers primarily in California, New York, Pennsylvania, and Texas.

The printing industry in the United States is large and diversified. Packaging materials, newspapers, periodicals, books, and business forms are the chief products. All large cities and most smaller ones have printing plants. By far the largest center is the New York City area.

are those that have been made into finished items from primary metals. Among them are forgings; stampings; hardware such as nuts, bolts, and screws; and metal cans and containers. The industrial areas of the Northeast and the Midwest lead in production. New England has long been a center of hardware manufacturing.

A variety of goods are produced in this group, including search and navigation equipment, medical instruments, photographic equipment, and watches and clocks. The northeastern states, especially New York and Massachusetts, lead in the production of most instruments. California is also important.

including pulp, paperboard, and various containers, are produced mainly in the Midwest and the South. Wisconsin leads all states in the manufacturing of these products. Minnesota, Georgia, and Pennsylvania are also important producers.

Primary metals are obtained from ores by smelting, refining, and other processes. Related products include metal plates, sheets, rods, bars, and foundry castings. Of all primary metals, iron and steel are produced in the greatest quantity. The nation has three main iron and steel centers—the Pittsburgh-Youngstown area, in Pennsylvania and Ohio; the Chicago-Gary area, on the southern shore of Lake Michigan; and the Buffalo-Cleveland area, on Lake Erie. Steel production, however, has declined substantially, by roughly a fourth, since peaking in the late 1960's.

Manufactured goods of lesser overall value include textiles and clothing; rubber and plastic items; stone, clay, and glass products; precision instruments; petroleum and coal products; lumber and wood items; furniture and office and store fixtures; tobacco products; and leather and leather goods.

The United States is one of the world's leading agricultural nations even though the relative importance of agriculture in the economy has declined steadily over the years. Farming now accounts for less than 3 per cent of the nation's labor force and about 2 per cent of the gross national product. Nevertheless, it makes the nation virtually self-sufficient in food and, by value, provides about one-eighth of the nation's exports of merchandise.

In the production of many farm commodities the United States ranks among the world's top producing countries. Among these products are corn, wheat, cotton, soybeans, peanuts, tobacco, citrus fruit, meat, milk, and eggs.

Since the 1930's agriculture has been marked by a large decline in the number of farms and a sharp rise in the average farm size. In the late 1980's there were about 2,170,000 farms; the average farm size was 460 acres (186 hectares). Large farms, those with more than 1,000 acres (405 hectares), account for roughly 60 per cent of all land in farms. Many of the largest farms are owned by corporations. Owners of small farms, because of high operating costs, often have difficulty in making a reasonable profit.

In general, agriculture is highly mechanized. Scientific methods of cultivation and livestock breeding are widely used. Hybrid seeds, chemical fertilizers, insecticides, and fungicides have contributed greatly to high crop yields. The average yield of corn per acre, for example, has tripled since the early 1940's.

By value, the leading farm products in the United States are cattle, milk, corn, soybeans, hay, and hogs.

The Midwest is the nation's leading agricultural region. It is the chief producer of corn, hogs, and soybeans and is a major producer of cattle, milk, wheat and other grains, and many fruits and vegetables.

New England is predominantly a dairying area. Farther south along the Atlantic seaboard, from New York to Maryland, farming is more varied. Among the items produced are dairy products, cattle, truck crops, and broilers.

Farming is also varied in the South, where cattle, soybeans, corn, tobacco, broilers, cotton, peanuts, dairy products, citrus fruit, and rice are among the chief farm products. Cotton, once the Smith's predominant crop, is the leading farm product only in Mississippi.

Throughout the Great Plains the raising of cattle and wheat prevails. Cattle are the chief source of farm income in most states in and west of the Rocky Mountains. Irrigation is practiced on the Great Plains and in the West. Highly specialized kinds of irrigated farming are practiced in parts of the West, particularly in California. By value of production, California is the nation's leading agricultural state. California produces dairy products, cotton, and many kinds of vegetables, fruits, and nuts in addition to cattle.

The fisheries of the United States are among the largest and most productive in the world. The United States has exclusive fishing rights in the area extending seaward 200 nautical miles (370 km) from the Atlantic, Gulf, and Pacific coasts, which total some 12,300 miles (19,800 km) in length. The United States also fishes in international waters, beyond the 200-mile limit.

The catch consists of both edible and inedible fish; the latter are processed mainly into meal and oil for industrial and agricultural use. Chief among the edible species, by total value, are salmon, shrimp, crabs, tuna, lobster, scallops, flounder, and oysters. Most of this catch is marketed fresh or frozen; the rest is marketed canned or cured. By tonnage, the catch of menhaden, an inedible species, surpasses that of any other fish, accounting, on the average, for roughly a fifth of the nation's total catch.

The Pacific catch accounts for nearly three-fifths of the total tonnage of fish caught; Atlantic and Gulf catches account for about a fifth each. The Pacific catch also leads in value of fish caught. Alaska and Louisiana are the top fishing states.

Commercial fishing on the Great Lakes is of limited significance, both in quantity and in value of the catch.

The West, with its vast evergreen forests, is the principal timber-producing area of the United States. Much of the lumbering there is done in large, scientifically managed forests owned by corporations. Vast tracts of federally owned land are also used for commercial production. Prominent among the species felled in the Western states—mainly for lumber and plywood—are Douglas fir, true firs, western hemlock, Ponderosa pine, and lodgepole pine. Oregon, California, and Washington are the leading timber-producing states in the West.

The South, with a warm, moist climate that promotes rapid forest growth, is the second-ranking lumbering region. It is primarily a producer of pines, particularly longleaf, shortleaf, loblolly, and slash pines. Lumber, pulpwood, and paper are the chief forest products of the South; Georgia is the leading producer.

Most of the nation's hardwood production comes from a band of deciduous forests extending from Missouri and Arkansas eastward to the Atlantic.

Mining employs less than 1 per cent of the labor force and produces only about 3 per cent of the gross national product. It is, nevertheless, a vital activity, supplying the raw materials needed by many other industries. Despite abundant and varied production, the United States is totally or heavily dependent on imports for numerous minerals. Among them are mica, manganese, bauxite, cobalt, chromium, platinum, asbestos, tin, nickel, potassium, zinc, mercury, and tungsten. Petroleum and petroleum products are the largest and most costly of the nation's mineral imports.

Fuels, primarily petroleum, natural gas, and coal, account for about 85 per cent of the value of all minerals produced. The chief oil-supplying states are Texas, Alaska, Louisiana, California, and Oklahoma. Natural gas comes mainly from Texas, Louisiana, Oklahoma, and New Mexico. Coal is the nation's most abundant fossil fuel, with estimated reserves sufficient to last for centuries. Kentucky, West Virginia, Wyoming, Pennsylvania, and Illinois are the leading producers of bituminous coal. Anthracite coal is mined in small amounts in Pennsylvania. Uranium, for nuclear reactors, is also mined, principally in New Mexico, Wyoming, and Texas.

The chief metals mined in the United States, by value, include copper, gold, iron, magnesium, silver, zinc, lead, and molybdenum. In general, the greatest quantities of metallic minerals are mined in the southwestern and Rocky Mountain states. Iron ore comes mainly from Minnesota and Michigan. Bauxite, nickel, tin, and tungsten are also produced.

Stone, sand, gravel, and other minerals used in building construction are produced in most states. Phosphate rock, used in making fertilizers and chemicals, is mined mostly in Florida and North Carolina. Sulfur and salt, which are also used in making chemicals, come mainly from the Gulf states. Large amounts of potash and other minerals are also produced.

The United States depends to a great extent on fossil fuels for energy. Petroleum products alone account almost 40 per cent of all the energy consumed, natural gas for about 24 per cent, and coal for about 22 per cent. Petroleum is used chiefly to provide fuel for transportation and heating, while coal provides the bulk of the power for generating electricity. Natural gas is consumed mainly by households for heating and cooking and by industrial users.

Hydroelectric, nuclear, geothermal, and solar power together provide about 26 per cent of the nation's energy. These energy sources are primarily used to generate electricity. Hydroelectric power is produced and used most extensively in the West and Pacific Northwest and in the Southeast. Nuclear power plants are scattered throughout the nation, but are most numerous east of the Mississippi. Solar and wind power are minor energy sources.

At the end of the 1990s the construction industry was the largest industry in the United States in terms of employment. Construction accounts for about 4 per cent of the gross domestic product. Since the end of World War II, a large increase in the nation's population and the expansion of suburbs and cities have generated much construction.

In general, housing is the leading type of construction-usually between one and two million new dwelling units, mostly single-family homes, are built each year. Office buildings, retail buildings, factories, facilities for public utilities, and highways make up a large part of the nonresidential construction. Most construction is privately financed; generally less than one-fifth is publicly funded. Since the 1950s there has been an especially large increase in construction in the Sun Belt and in the West. California, Texas, and Florida usually lead the nation in new construction.

Commercial banks, savings and loan associations, credit unions, insurance and finance companies, and other financial institutions account for about one-seventh of the gross national product. The 50 largest commercial banks, many of them international in scope, hold roughly 40 per cent of the banking industry's total deposits. Most of the largest banks are in New York, California, Texas, and Illinois. New York City has long been the nation's principal financial center and home of its principal stock exchanges. Smaller stock exchanges are located in Boston, Philadelphia, Chicago, and San Francisco.

Most financial institutions are regulated by the federal government, some by the states. The Federal Reserve System exercises certain central banking functions.

Technological advances in communications and data processing have permitted financial institutions to expand their role in the economy greatly. For example, the bank credit card—whose widespread use was made possible by computerized billing and collection systems—has replaced the use of cash in many transactions.

The United States has a vast system of railways, highways, and pipelines, and virtually every large city is served by a commercial airport. Inland waterways provide important transportation routes in many parts of the country.

In the mid-1990's about 38 per cent of intercity freight shipments (in ton-miles) were by rail, 28 per cent by truck, 18 per cent by pipeline, 15 per cent by inland waterway, and less than 1 per cent by air. Passenger traffic (in passenger-miles) during the same period was handled primarily by automobiles—about 81 per cent according to government estimates. Airlines accounted for 17 per cent of the passenger-miles, railways and huses for the remainder.

In the mid-1990's there were about 3,905,000 miles (6,284,000 km) of roads, highways, and streets in the United States—the largest highway system in the world. Roughly four-fifths of the mileage is accounted for by roads and highways in rural areas, connecting cities and towns. Most of the roads are hard-surfaced.

The best highways are those of the Interstate system, a national network of highspeed, limited-access superhighways linking the major cities. The system, begun in 1956. totals about 45,600 miles (73,200 km). In addition to the Interstate system there is a much larger network of federally aided state roads known as "US highways."

Railway mileage in the United States has declined steadily since the 1930's. In the mid-1990's there were about 169,000 miles (272,000 km) of tracks. The volume of traffic hauled by rail, however, has increased steadily despite severe competition from trucks, barges, and pipelines.

Unlike railways in most other countries, those in the United States are privately owned and operated. Most intercity passenger trains, however, are operated by Amtrak, a government-controlled corporation. Some privately owned railways still provide commuter service.

Since the first successful flight of the Wright brothers at Kitty Hawk, North Carolina, in 1903, the United States has been a leader in developing aviation. All large cities and many smaller ones are served by one or more of the many scheduled airlines. A number of domestic lines and dozens of foreign lines provide international flights. Air travel is especially important in Alaska and in connecting Hawaii with the mainland. Chicago's O'Hare and Atlanta's Hartsfield are the busiest commercial airports in the nation.

The nation's most heavily utilized waterway consists of the Mississippi River and its major tributaries, including the Illinois, Missouri, and Ohio rivers. The Great Lakes also provide excellent transportation, especially for bulk cargo such as iron ore, coal, and grain. The St. Lawrence Seaway, opened in 1959, links the Great Lakes and the Atlantic Ocean.

The Intracoastal Waterway is a largely sheltered route extending along the Atlantic and Gulf coasts. Major shipping canals are the Cape Cod Canal and the Chesapeake and Delaware Canal, both part of the Intracoastal Waterway; and the Chicago Sanitary and Ship Canal, the Sault Ste. Marie Canal, the Houston Ship Channel, the New York State Barge Canal, the Sacramento Deep Channel, and the Lake Washington Ship Canal.

The United States' merchant marine has declined sharply since the 1950's, mainly because of greatly increased foreign competition and the registration of many American-owned ships under foreign flags. As a result, only a small part of the nation's foreign trade is carried on ships flying the United States flag.

In terms of total tonnage, the leading shipping area is the Gulf Coast, whose ports include New Orleans, Houston, and Baton Rouge. Petroleum accounts for much of the Gulf Coast tonnage. In terms of total value, the leader is the Pacific Coast. Major ports here include Los Angeles, Long Beach, Oakland, San Francisco, Portland, and Seattle. Major Atlantic ports include New York City, Philadelphia, and Baltimore.

provide a relatively cheap means of moving crude petroleum, petroleum products, natural gas, and other commodities. In the early 1990's some 420,000 miles (676,000 km) of petroleum and natural gas pipelines were in operation, excluding intrastate lines. Products flow in greatest quantity from the Gulf Coast and southern Great Plains northeastward to the Midwest and Atlantic Coast.

Unlike communication facilities in most other countries, those in the United States are, for the most part, privately owned and operated, with the federal government serving as a regulatory body. Only the postal service is operated by the federal government.

Tremendous advances in communications technology have been made since the 1960's, notably the use of artificial satellites to relay television, telephone, and other transmissions. The Communications Satellite Corporation (COMSAT), a privately owned American company, provides international, maritime, and domestic communications satellite services—linking the United States with most countries of the world.

Virtually all households in the United States have television sets, the great majority of which are color sets. Four major commercial TV networks—ABC, CBS, NBC, and Fox—broadcast nationally, and there are more than 1,000 local commercial stations, most of them affiliated with the major networks. Commercial stations receive their revenue from advertisers. There is also a public television service—PBS—which is funded by the federal government and private sources. Cable television, available in most parts of the country, is operated on a subscription basis. AM and FM radio stations, most of them supported by advertising revenue, numbered about 10,000 in the early 1990's.

Periodicals, and Books. Roughly 1,700 daily newspapers and 8,200 weekly newspapers are published in the United States. In major cities, there are also foreign-language dailies. Virtually all the newspapers have regional readerships; only a few, notably the Christian Science Monitor, the New York Times, USA Today, and the Wall Street Journal, are circulated nationally.

The number of periodicals and books published in the United States has increased dramatically since the 1950's. Today, there are more than 11,300 periodicals, and each year more than 46,000 new book titles and editions are published.

The telephone is one of the most extensively used means of communication in the United States. Virtually every household has telephone service. Seven major regional companies and about 1,300 local companies, which are regulated by the states, provide wiring and local connections. American Telephone and Telegraph, General Telephone and Electronics, MCI Communications, US Sprint, and many smaller companies provide long-distance service.

Retail and wholesale trade together account for about 17 per cent of the gross national product and about 21 per cent of the labor force. Retail trade is conducted, to a large extent, by corporate-owned chain stores. The leading types of retail establishments, by gross sales, are grocery stores, motor vehicle dealers, department stores, restaurants, and gasoline service stations. Discount stores, franchised fast-food shops, and manufacturers' outlets have had especially rapid growth during the past few decades. Since the 1960's suburban shopping centers and malls have substantially increased their share of the retail market.

Wholesale trade is transacted mainly by wholesale merchants, manufacturers' sales agents, and brokers. The leading goods sold by wholesalers are processed foods and farm commodities, machinery, motor vehicles and equipment, petroleum products, and electrical goods. California, New York, Texas, and Illinois are the chief states in wholesale trade.

The United States leads all other countries in foreign trade, usually conducting about a seventh of the world's total (by value). In the early 1990's the nation's imports and exports amounted to a total of more than 885 billion dollars annually.

Until the 1970's exports exceeded imports in value, producing a favorable balance of trade. The first trade deficit in more than 75 years occurred in 1971 and was followed by more deficits and by devaluations of the dollar. Soaring costs of petroleum imports contributed heavily to the imbalance of the nation's foreign trade.

Canada is the chief trading partner; Japan, Mexico, Great Britain, and China also are major trade partners. The United States also trades to some extent with virtually every country in the world.

Exports consist largely of manufactured goods. Most important is machinery. Transportation equipment, mainly motor vehicles and aircraft, chemicals, and electronic devices and equipment are also major exports. The principal nonmanufactured goods exported are farm products—chiefly soybeans, vegetables and fruits, meat, corn, and animal feeds—and coal and lumber. Because of food shortages threatening much of the world, the demand for United States farm products, especially soybeans, has mounted sharply.

Imports consist primarily of crude petroleum, petroleum products, and manufactured goods. Transportation equipment, mainly automobiles, and machinery are the leading manufactured imports. Other imports include chemicals, iron and steel products, nonferrous metals, paper and newsprint, textiles, clothing, footwear, alcoholic beverages, lumber and wood pulp, and metal ores and scrap. Imported foods include fresh and processed meat and fish, coffee, sugar, and tropical fruits.

Since about 1950, services have accounted for a growing share of the gross national product, a sign of their increasingly important role in the economy. Today the service sector accounts for about a fifth of the GNP and employs about a third of the labor force.

Services in the business field—including such activities as product research and development, data processing, consulting, and advertising—are among the fastest-growing segments of the service sector. Data processing, which was virtually nonexistent until the 1960's, accounts for much of the growth in business services. Health care services have also expanded tremendously. Health care and business services generate the two largest shares of income from the service sector of the economy.

During the last several decades of the 20th century, hotels, motels, restaurants, and travel-related services (such as travel and car rental agencies) expanded, as travel in general increased. Also contributing substantially to the economy are such other service activities as legal work, engineering, repair work, and entertainment.

Government at the federal, state, and local levels is a major force in the nation's economy as a consumer and employer. At the end of the 20th century, government accounted for about one-ninth of the gross national product and a seventh of the labor force. Government employees include legislative, judicial, civil service, and military personnel; teachers; librarians; police officers; and fire fighters. The federal government is the largest single buyer of goods and services in the nation. Federal contracts provide the bulk of the business done by some of the country's largest corporations. Federal grants finance much of the nation's research activities.

Most government expenditures are financed through taxation; the rest, to an increasing extent, through borrowing. Federal spending is mainly for national defense; income security programs, such as social security and unemployment benefits; interest on the national debt; health; education; and veterans' benefits. At the state and local level expenditures are mainly for education, public welfare, highways, health, and interest on debt.

Agriculture was the dominant economic activity of the United States from early colonial times until about the end of the 18th century. Most factory-made goods were imported, mainly from Great Britain. Many products, mostly household and personal items, were made either at home or by artisans in small shops. Maritime commerce and shipbuilding were significant activities, as were fishing and whaling in Atlantic waters. Vast virgin forests provided timber for the construction of ships and homes; wood was extensively used as fuel. Power for mills was provided by water wheels at rapids and falls.

The early 19th century brought increasing industrial growth as a result of improved transportation, new inventions, and freedom from foreign intervention. Steam engines, steamboats, and canals contributed much to the growth. Coal from the Appalachians was used increasingly for fuel. Inland, the fertile agricultural lands of the central United States were opened as railways and settlements spread westward across the land. By the mid-19th century railways had replaced steamboats as the nation's chief means of transportation. In the South, the collapse of slavery after the Civil War brought a virtual end to the plantation system and the beginning of an era of small farms.

Rapid industrialization followed the Civil War, especially in the East and the Midwest. Contributing to the growth were a seemingly inexhaustible supply of natural resources, the increased use of mass-production methods, the development of large corporations, and an ever-expanding national market. Cheap immigrant labor also promoted rapid industrial growth. Toward the end of the century electric power became increasingly available. By the time of World War I the United States was a major industrial power.

Economic development in the West lagged behind that in the eastern part of the nation. Much of the West did not become part of the United States until the late 1840's, and in the early years trapping and the trading of furs were the only significant economic activities in many parts of the West. Mid-century gold rushes in California and Colorado brought many miners and the first large influx of permanent settlers to the region. The opening of transcontinental railway lines, beginning in 1869, provided an efficient means of moving goods and passengers between the East and the West. Later, the opening of the Panama Canal also helped tie the West more closely to the rest of the nation. Mining, cattle ranching, lumbering, irrigated farming, and commerce eventually became the economic mainstays of the West.

Except for the depression years of the 1930's, the economy of the United States expanded almost uninterruptedly after World War I. The use of moving assembly lines greatly increased production. Enormous industrial expansion occurred during and after World War II. Much of the 20th-century expansion was caused by diversification of products due to technological change. The automobile, chemical, electrical, computer, aerospace, and telecommunication industries brought about far-reaching social as well as economic change.

Automation—the use of machines requiring little or no human assistance—was increasingly used after the mid-1900's. During the same period much industrial growth occurred in the southern and southwestern states, the so-called Sun Belt, and on the West Coast, often at the expense of eastern and Midwestern states.

A mixed economy has evolved in the United States, largely since the 1920's. It is a combination of capitalism, with a degree of government regulation, and of socialism, with such enterprises as the postal system, local transit systems, and the Tennessee Valley Authority being government-operated. The economy is broad-based, but depends most heavily on manufacturing and the service industries. The nation's vast mineral resources, efficient transportation and communication systems, and technological skills help provide the people of the United States with one of the highest standards of living in the world.

The People

A census has been taken every 10 years since 1790. In 2000, according to the Bureau of the Census, whites made up 75.1 per cent of the population; blacks 12.3 per cent; Asians and Pacific Islanders 3.7 per cent; American Indians, Eskimos, and Aleuts 0.9 per cent; those of some other race 5.5 per cent; and those of more than one race 2.4 per cent. People of Hispanic origin (of any race) made up 12.5 per cent of the population.

The South had long been the home of most blacks. In the 1930's blacks began to move in increasing numbers to the industrial cities of the North. During the 1970's, however, there was also some migration of blacks to the South. The states with the largest black populations in 2000 were New York, Texas, Georgia, Florida, California, and Illinois.

American Indians live in all states, but the great majority live in the West and the South. Five states—Arizona, Oklahoma, California, New Mexico, and North Carolina—account for the majority of the Indian population. The vast majority of the Eskimos live in Alaska.

In 2000, Hispanic Americans became the nation's largest minority. Nearly 60 per cent trace their origins to Mexico, and more than 9 per cent, to Puerto Rico. California, Texas, New York, and Florida had the largest numbers of Hispanic Americans in 2000.

The Chinese—largest of the Asian and Pacific Islander groups—live mainly in California and New York. The Filipinos and the Japanese are concentrated largely in California and Hawaii, Asian Indians in New York and California. California is the home also of most of the Koreans, Vietnamese, Samoans, and Guamanians.

Some southern and many western states have gained population extremely rapidly, especially since 1940. Among these are California, Colorado, Arizona, Nevada, and Florida. California has grown spectacularly. In 1950 it replaced Pennsylvania as the second-ranking state, and by 1970 it had replaced New York as the most populous state. Among southern states, Texas and Florida have had the most rapid population increases. Nevada experienced the largest percentage of increase during 1990–2000, slightly more than 66 per cent.

The East North Central and Middle Atlantic states were among the most heavily populated until the 1970's and 1980's. These include New York, which had the largest population until 1970; Illinois; Pennsylvania; Ohio; Michigan; and New Jersey. Since the 1930's, most of these long-established, industrial states have had only moderate rates of population increase.

Population density varies widely from state to state. New Jersey, with 1,134.2 persons per square mile (437.9 per km2) in 2000, and Rhode Island, with 1,003.2 (387.4), were the most densely populated states. The eight Mountain states had densities ranging from Wyoming's 5.1 persons per square mile (2.0 per km2) to Arizona's 45.1 (17.4). Alaska, with 1.1 persons per square mile (0.4 per km2), was the most thinly populated state.

Urban areas include all incorporated and certain unincorporated places of 2,500 residents or more and the suburbs of all cities of 50,000 or more. During the course of the country's development, farming has become more efficient, and people have turned in ever-increasing numbers to the cities for their livelihoods. Between 1790 and 1990 the rural population dropped from 95 to 25 per cent.

The mushrooming of suburbs around large cities has been especially rapid since 1940. These sprawling urban areas, including cities and suburbs, form metropolitan areas. Slightly less than three fifths of the nation's people live in metropolitan areas of more than 1,000,000 people.

As a vast young country offering great opportunity, the United States has been a magnet for immigrants since its earliest days. The early colonists were mainly English, but there were also Dutch, German, Scotch-Irish, and French Huguenot settlers. In 1790, these people and their descendants made up about 80 per cent of the population. The remaining 20 per cent was made up largely of blacks. Many of these had been brought from Africa and the West Indies as slaves, and many were born in America of slave parents.

Beginning in the 1820's and 1830's, immigration increased rapidly, with people coming from so many countries that America came to be called a "melting pot" of nationalities. During the depression of the 1930's more foreign born left the country than were admitted. After World War II immigration increased. Of the nearly 57,000,000 immigrants who arrived during 1820–1990, the largest numbers came from Germany, Italy, Great Britain, Ireland, Canada, Mexico, Austria, Russia, Caribbean countries, and Sweden.

Freedom in matters of education and the right of every child to have an education are basic principles in the United States. Unlike many other nations, the United States does not have a central or federal system of education. Establishing and administering public schools is one of the p/wers exercised by each state. The state, in turn, delegates much of this responsibility to local school districts. There are both similarities and differences in the educational systems of the 50 states.

The federal government has, however, deep interest in the education of persons of all ages. Federal financial aid is given to the states and local school districts for specified educational purposes, such as the work of land-grant colleges and universities; vocational education below the college level; and improvement of the education of children of low-income families. The federal government also provides scholarships for college students. Four college-level academies for the armed forces and one for the Merchant Marine are supported entirely by federal funds, and a number of specialized institutions, such as Gallaudet University (for the deaf), receive major financial support directly from the federal government.

The main federal agency dealing with education is the U.S. Department of Education, but other departments, most notably the Department of Agriculture, also have educational functions.

In 1990 public school systems in the United States had a total of approximately 61,300 elementary schools and 22,700 secondary schools. Parochial and other private elementary schools numbered about 22,200 and secondary schools, 9,000. There were more than 1,600 public and 2,000 private institutions of higher education.

Teachers at all levels of instruction totaled some 2,753,000 in 1990—1,680,000 in elementary schools, 1,073,000 in secondary schools, and 840,000 (including part-time staff) at the college level. Overall, about 70 per cent were employed in public schools.

Enrollment in public schools was about 27,050,000 in kindergarten through grade 8; 14,167,000 in grades 9–12; and 10,844,000 in higher education. Private schools had a total enrollment of approximately 4,095,000 in kindergarten–grade 8; 1,137,000 in grades 9–12; and 2,975,000 in institutions of higher education.

Literacy in the United States is high. In 1990 the Bureau of the Census estimated that only one half of one per cent of all persons 14 years old and over were illiterate (unable to read and write in any language). In 1870, 20 per cent of all persons over 10 years of age were illiterate.

No other country in the world has a greater variety of religions, communions, denominations, and sects than the United States. Nearly all branches of Christianity and almost all Protestant denominations are represented. Christians make up approximately 60 per cent of the population. Nearly half the Jews in the world live in the United States; they make up 2.6 per cent of the population. Other religious groups include Muslims, Sikhs, Hindus, Buddhists, and Bahá'ís.

More than 220 of the nation's Christian denominations reported membership statistics in the mid-1990s, and their total membership was more than 155,000,000. Of this total, approximately 55 per cent were Protestants; 38 per cent, Roman Catholics; and 2.6 per cent, members of Eastern Orthodox churches. The largest Protestant denomination is the Southern Baptist Convention, with about 15,360,000 members.

Religious freedom and separation of church and state are traditional in the United States. Government cannot interfere with religion or show preference for one religion over another. It cannot set up an official, or established, church, nor give support to any religion or to all religions. These principles as laid down in the First Amendment to the U.S. Constitution apply to the federal government but in effect also bind the states.

In colonial times the Congregational Church was established in Massachusetts, Connecticut, and New Hampshire. The Church of England was the official church in New York and in the southern colonies. Rhode Island and Pennsylvania were centers of religious freedom. Late in the colonial period the Presbyterians and Baptists became strong. After the American Revolutionary War there were religious revivals in which the Methodists were active. The Roman Catholic Church was weak during the colonial period, but after 1830 it grew rapidly because of immigration. Many other communions and denominations were brought to the United States by immigrants.

In the early days of the republic, United States artists and writers were generally regarded as inferior to those in Europe. By the end of the 19th century, however, an independent national literature of high quality had been established by such writers as Washington Irving, Edgar Allan Poe, Walt Whitman, and Mark Twain. In the 20th century, such American authors as Sinclair Lewis, Eugene O'Neill, William Faulkner, Ernest Hemingway, John Steinbeck, Saul Bellow, and Isaac Bashevis Singer were recognized with Nobel prizes in literature.

Three outstanding 20th-century American-born poets—Robert Frost, Ezra Pound, and T.S. Eliot—had to go to Europe for first recognition, and Pound and Eliot remained expatriates. But the worth of such leading poets as Carl Sandburg, Marianne Moore, William Carlos Williams, Theodore Roethke, and Robert Lowell was appreciated at home from the first.

John Singleton Copley and Benjamin West were the first native artists to become famous in the United States. Artists were generally neglected, however, and many of them felt it necessary to study and work in Europe. In the 20th century, American contributions were recognized. Alexander Calder's mobiles introduced motion into sculpture. Jackson Pollock's action painting expanded the field of Abstract Expressionism. Pop art was a significant American innovation.

Music in the United States was strongly influenced by European music, and study in Europe was considered a necessary part of musical training far into the 20th century. America's most influential contribution to music was jazz, a form originated by blacks and based on African rhythms. The musical, which evolved from burlesque and operetta, was another American innovation.

For many years, architects in the United States simply adapted European styles to American climate, landscapes, and materials. Greater independence was manifested in the late 19th and early 20th century. Louis Sullivan and other Chicago architects developed the skyscraper. Frank Lloyd Wright, a student of Sullivan's, brought originality into private as well as public buildings. Louis I. Kahn, Eero Saarinen, I. M. Pei, and Paul Rudolf were noted for freshness and vitality in designs and techniques and richly imaginative use of materials.

Scientific achievement began early in the history of the United States, and American inventions and technology have helped to give the nation one of the highest living standards in the world. Americans have long held commanding positions in almost every branch of both basic and applied science. Benjamin Franklin was noted not only as a statesman but also as a scientist. The contributions of such inventors as Samuel F. B. Morse, Alexander Graham Bell, and Thomas Edison brought the world rapid communication and ushered in the electrical age. Eli Whitney, Henry Ford, and others introduced mass production. The atomic age was born in the United States through the work of both American and foreign scientists. More than one-third of the Nobel prizes in chemistry, physics, physiology and medicine, and economics have been awarded to Americans.

The Nobel Peace Prize has been awarded to more Americans than to citizens of any other single country. Recipients include Theodore Roosevelt, Woodrow Wilson, Jane Addams, George C. Marshall, Martin Luther King, Jr., and Henry Kissinger. The work of William James and John Dewey in philosophy, psychology, and education is of worldwide importance. Presidents George Washington, Thomas Jefferson, and Abraham Lincoln are admired throughout the world.

There are about 5,500 museums in the United States. Prominent among these are the Metropolitan Museum of Art in New York City, the Field Museum of Natural History in Chicago, and the Smithsonian Institution in Washington, D.C. Nearly every major United States city has a symphony orchestra. Those of Chicago, Boston, New York, and Philadelphia rank with the world's greatest.

There are hundreds of opera groups in the country, ranging from small opera workshops to major professional companies. The Metropolitan Opera Company of New York City has long ranked as one of the foremost in the world. Other notable groups are the Lyric Opera of Chicago, Opera Company of Boston, New York City Opera Company, and San Francisco Opera Company. Many metropolitan areas also support ballet and modern dance companies. Among those nationally known are the American Ballet Theatre and the New York City Ballet.

Almost every town has a public library, and bookmobiles reach people in rural areas. The largest collection of books and pamphlets in the United States is found in the Library of Congress. The New York Public Library is the largest public library in the nation. The library of Harvard University, founded in 1643, is the country's oldest and largest institutional library.

With the number of universities, colleges, and junior colleges exceeding 3,000, higher education in the United States is more widely available than in any other major country. Americans once turned to Europe for advanced study, but since the early 1900's the great American universities have equalled or surpassed foreign ones in many fields. Educational foundations established by Andrew Carnegie, John D. Rockefeller, Henry Ford, W. K. Kellogg, and other wealthy individuals provide funds for books, scholarships, and research.

The favorable economic position and amount of leisure enjoyed by the people of the United States give them unusual opportunities for recreation. Paid vacations became the rule for most industrial and office workers in the years following World War I. Wide ownership of automobiles makes national and state parks, monuments, historic sites, and recreational areas easily accessible to millions of tourists each year. Many American tourists travel abroad.

The most popular outdoor spectator sports are football and baseball. Horse racing and automobile racing have large followings. Soccer does not have the popularity it enjoys in many other countries, but interest in it is increasing. Indoor spectator sports include basketball and hockey. Participant sports are many and varied. Bowling, golf, tennis, skiing, skating, bicycling, running and jogging, hunting, fishing, and swimming, boating, water skiing, and other water sports are very popular.

The United States is a democratic federal republic under the Constitution of 1787 and its amendments. There are three levels of government: (1) national, or federal; (2) state, consisting of 50 separate governments; and (3) local, consisting of thousands of county, township, city, and other local units within the states.

The U.S. Constitution, the oldest written constitution among the great nations, has served as a model for a number of other countries. The Presidential system of government, with separation of powers between the executive, legislative, and judicial branches, is one of the two leading forms of democratic government in use today. (The British parliamentary system is the other.) The emphasis on freedom in the Declaration of Independence, the Constitution, and the Bill of Rights has been an important world influence.

The United States form of government is based on these principles:

• Popular Sovereignty. Supreme power is in the hands of the people. Government is based on the consent of the governed, as expressed through the United States Constitution, elections, and public opinion.
• Constitutionalism, or Limited Government. The U.S. Constitution is the supreme law. Every government—national, state, and local—and every citizen must abide by its provisions. The national and state constitutions have bills of rights that guarantee certain basic rights to the individual.
• Federalism. Governmental powers are divided between the national government and the states. Whatever powers are not granted to the national government by the Constitution are reserved to the states or to the people.
• Representative Government. As a republic and representative democracy, the government is run by representatives chosen directly or indirectly by the voters to express and enforce their will.
• Separation of Powers. Governmental powers are divided among three generally coordinate (equal-ranking) branches: legislative, executive, and judicial. To prevent any one branch from taking over the functions of another, the power of each branch is checked and balanced by the powers of the other two. The President, as chief executive, has the power to veto, or refuse to give consent to, legislation. Laws must be approved by both houses of Congress, the legislative body. And through the power of judicial review, the courts can invalidate laws and actions that are contrary to the Constitution.

The U.S. Constitution creates the three branches of government and defines their powers; determines the relations between federal government and states; denies certain powers to both the national government and the states; and guarantees certain rights to the people.

Power to make laws, or legislate, is vested in the Senate and House of Representatives, the two elected houses of Congress. Congress has both express powers (enumerated in the Constitution) and implied powers (those necessary and proper to carry out the express powers).

Executive power is vested in the President. He and the Vice President are elected for four-year terms. The President supervises law enforcement, conducts foreign relations, is commander in chief of the armed forces, and recommends legislation to Congress. With Senate approval he appoints federal judges; ambassadors; and heads of executive departments, Executive Office branches, and independent agencies.

The Executive Office of the President consists of assistants, bureaus, and councils that aid and advise the President in his various roles. Branches of this office include the following:

The White House Office.It maintains communication with Congress and executive departments and agencies; arranges the President's schedule; and performs clerical duties for the President. Members of the staff include the chief of staff to the President, the President's counsel, various assistants to the President and special assistants, and the President's private secretary, press secretary, and military aides.

Office of the United States Trade Representative. It assists the President in executing trade agreements.

Council on Environmental Quality. It aids the President in formulating national policies on the environment.

Other Executive Office Branches: See Council of Economic Advisers;National Security Council;Office of Management and Budget.

There are 15 executive departments; their heads automatically become members of the President's cabinet.

Independent agencies are created by Congress to carry out functions that do not fit into existing executive departments. There are more than 50 such agencies. With respect to their powers, most of these agencies are independent of both the President and Congress. Many of them are regulatory agencies that supervise various commercial activities and, as such, have limited judicial and legislative powers.

Most of the independent agencies are governed by boards or commissions appointed by the President with the consent of the Senate. Commissioners or board members are usually appointed for definite terms that do not coincide with the term of office of the President, so that the agencies will be as non-political as possible.

Judicial power is vested in the Supreme Court and in other federal courts created by Congress. The Supreme Court interprets the Constitution and the laws. It sometimes invalidates laws of Congress and of the states and also nullifies actions by the executive branch.

The permanent seat of the federal government is the District of Columbia. The district itself has an elected mayor and 13-member city council. The U.S. Congress, however, controls the city's budget and has the power to rescind any council action.

Each state has its own constitution. The typical constitution has a preamble, a bill of rights, sections creating the three branches of government and defining their powers, provisions on local government, and a section on constitutional amendment.

Under the federal system the states may exercise all governmental powers except those given to the national government and those prohibited to the states by the U.S. Constitution.

Except for Nebraska, which has a one-house legislature, each state has a legislature of two houses, both elective. In most states the lieutenant governor presides over the senate. Usually the other house elects a speaker as its presiding officer. In some states the people may pass laws directly by initiative and referendum.

Every state elects a governor as chief executive for a term of two to four years. Most of the states elect a lieutenant governor; he succeeds a governor who dies or cannot serve. In every state but North Carolina the governor can veto laws passed by the legislature. In some states he can veto individual items in bills.

Most states elect several administrative officials, including lieutenant governor, secretary of state, attorney general, treasurer, auditor, and superintendent of public instruction. Many states also have various administrative departments, each usually headed by a director appointed by the governor. Some states have various boards and commissions over which the governor may have little control.

On the lowest level there are usually justices of the peace in rural areas and municipal courts in cities. Next are the trial courts, which handle most cases. Above them are the courts of appeals, and finally the state supreme court.

The United States has about 81,000 local governmental units. These local units are created by the state as agents of the state; they have only such powers as the state gives them. The states delegate many of their responsibilities to local governments because the work can be done more efficiently on the local level.

The largest of the local administrative units is the county. Each state—except Alaska—is divided into counties (called parishes in Louisiana). In Connecticut and Rhode Island, however, counties are only geographical designations for election or judicial purposes and do not have governmental structures. Alaska is divided into boroughs (which are similar to counties) and "census areas," established for statistical purposes.

Townships usually are subdivisions of the county created to meet local needs in rural areas. In New England, however, the town (as the township is called there) is the chief unit of local government. Township government is generally restricted to the Northeast and Midwest. Where townships exist in the South and Far West, they are mainly geographical designations.

include cities, boroughs (except in Alaska), towns (outside New England), and villages. They are special governmental units organized to meet the needs of urban areas. For judicial and certain other purposes, most municipalities remain within the jurisdiction of the county in which they are located. Some cities are entirely independent, not being within any county at all.

School districts are the most numerous of these subordinate governmental units. Special districts have also been created for sanitation, navigation, drainage, conservation, and other purposes.

In some areas, metropolitan governments have been formed by municipalities and counties to handle regional problems. Sometimes a separate unit is established and delegated certain powers. In other cases, the municipal and county governments may be consolidated into one governing body.

The United States has sovereignty over a number of outlying areas. Most of these areas are under the jurisdiction of the secretary of the interior, assisted by the Office of Territorial Affairs. Exceptions are Puerto Rico and the Northern Marianas, which are self-governing commonwealths. All have internal self-government. Most have elected governors and legislatures.

Residents of Puerto Rico, Guam, the United States Virgin Islands, and the Northern Marianas are United States citizens. Those of the other areas are not. .

The President is commander in chief of the armed forces of the United States, assuring civilian control of the military establishment. The National Security Act of 1947 placed the army, navy, and air force under a single civilian secretary of defense, who is a member of the President's cabinet. (Previously, the army and navy had separate cabinet-level secretaries, and the air force was part of the army.)

The President is advised and assisted in matters of defense by several other agencies in addition to the Department of Defense. These include the National Security Council and the Central Intelligence Agency.

In addition to the army, navy, and air force, the armed forces include the Marine Corps, which is part of the navy; and the Coast Guard, which is part of the Department of Transportation in peacetime but comes under navy control during war.

The National Guard and Air National Guard are reserve units ordinarily under control of the states. A governor can call out his state's guard units to deal with riots, disasters, or other emergencies. In time of national emergency, guard units may be called into federal service. The National Guard and Air National Guard are supported by federal funds.

The United States maintains one of the world's largest and best-equipped military forces. For the numbers of men and women on active duty in the armed forces and serving in the various military reserve units, see separate articles on the branches of service—army, navy, air force, Marine Corps, and Coast Guard—and the article on the National Guard.

table titled Major Combat Vessels of the Leading Navies.

All branches of the armed forces have guided or ballistic missiles. National defense spending has been a substantial percentage of the national budget nearly every year since 1942.

Each branch of the armed forces has its own program for securing both enlisted and commissioned personnel for its active and reserve components. Great emphasis has also been given by all branches in recent times to the recruiting of women. Conscription (the draft) was abolished in 1973. Beginning in 1980, young men were again required to register, but the draft itself was not reinstated.