Four Sections of the Rockies
The Rockies are often divided into four sections—Southern, Middle, Northern, and Arctic Rockies.
The Southern Rockies extend from northern New Mexico to southern Wyoming as nearly parallel north-south ranges. Separating the ranges are high valleys and broad basins, some of which are called parks. Among the principal mountain ranges are the Sangre de Cristo and San Juan mountains in New Mexico and Colorado; the Sawatch, Front, and Park ranges in Colorado; and the Medicine Bow Mountains in Colorado and Wyoming.
The Southern Rockies contain the loftiest peaks in the entire system. Colorado's Mount Elbert in the Sawatch Range, reaching 14,433 feet (4,399 m), is the highest. More than 55 other peaks, all of them in Colorado, exceed 14,000 feet (4,267 m).
The Middle Rockies begin at the Wyoming Basin, a western pocket of the Great Plains, and lie mainly in parts of Utah, Idaho, and Wyoming. Extending in many directions, the ranges are scattered and present no solid front on the Great Plains. The chief ranges include the Snowy, Absaroka, Teton, and Wind River ranges and the Bighorn Mountains in Wyoming and the Wasatch Range and Uinta Mountains in Utah. Wyoming's Gannett Peak, 13,804 feet (4,207 m), is the highest mountain.
The Northern Rockies extend northwestward from Montana, Idaho, and Washington for more than 900 miles (1,450 km) into Canada. The largest of the many ranges in the United States section include the Clearwater, Salmon River, and Sawtooth mountains in Idaho and the Bitterroot Range along the Idaho-Montana border.
In Canada the Rockies rise abruptly from the Great Plains. They have been heavily glaciated, and many sections are extremely rugged and scenic. Snow fields and glaciers still exist in some areas. Mount Robson, a 12,972-foot (3,954 m) peak in British Columbia, is the highest point in the Northern Rockies. West of the Canadian Rockies, and running parallel to them, is the Rocky Mountain Trench, a deep valley with steep walls. West of the trench rise the Purcell, Selkirk, and Monashee mountains, collectively known as the Columbia Mountains. The Cassiar and Stikine mountains, in the north, join the Arctic Rockies.
The Arctic Rockies begin in northern British Columbia, run northwestward, then westward, and end at the Arctic Ocean in northwestern Alaska. The mountains are a series of relatively low and disconnected ranges, the chief ones being the Mackenzie and Richardson mountains along the Northwest-Yukon territories boundary and the Brooks Range in Alaska.
