Ohio lies within two large geographic regions of the United States. Eastern Ohio is within the Appalachian region of the eastern United States. The rest of the state is within a large lowland region, which covers most of the Midwest.
The Appalachian Plateau is gently rolling in the north, where receding glaciers smoothed the terrain. The southern portion was not affected by glaciation and has rougher terrain. Elevations in the Appalachian section vary from about 600 feet (180 m) in the river valleys to about 1,400 feet (430 m) in the hills. An area of low hills and ridges borders the lowlands.
The Central Lowlands region was strongly affected by glaciation during the last ice age. The northernmost section is a relatively flat plain that was once the floor of a large glacial lake. In the central and southern portions, debris deposited by receding glaciers created a primarily gently rolling landscape, with broad valleys and some high hills. Found in the central area is Campbell Hill, the highest point in the state—reaching 1,550 feet (472 m) above sea level. The state's lowest point, 433 feet (132 m) above sea level, is found at the confluence of the Ohio and Great Miami rivers in the extreme southwest.Ohio's state flower is the scarlet carnation.
The glaciers that once covered much of Ohio left no major natural lakes except Lake Erie. Most of Ohio's lakes are artificial, created mainly for flood control and water supply. The largest artificial lake is Pymatuning Reservoir at the Ohio-Pennsylvania border. Lake Erie, touching the eastern two-thirds of Ohio's northern border, is an important transportation route. It is rivaled as the state's most important water route only by the Ohio River, one of the nation's busiest waterways.
The Ohio River and its chief tributaries within the state (the Miami, Scioto, and Muskingum) drain the southern two-thirds of the state. The north is drained by the Maumee, Sandusky, Cuyahoga, and several smaller rivers, flowing into Lake Erie.
Ohio has a humid continental climate, similar to that of the rest of the Midwest. It has relatively warm summers and cold winters, with year-round precipitation. Average July temperatures range from 71° F. (22° C.) in Cleveland, in the northeast, to 76° F. (24° C.) in Cincinnati, in the southwest. In January Cleveland averages 27° F. (-3° C.); Cincinnati, 31° F. (-1° C.). Average annual precipitation for the state varies from 30 to 40 inches (760 to 1,020 mm), with the greatest amount falling in the southwest. Snowfall is moderate, with the maximum falling along the lake. Precipitation is heaviest in spring and summer. Spring rains combined with melting snow have occasionally caused disastrous floods, especially along the Ohio River.
Before settlers arrived in Ohio, forests were the dominant type of vegetation. Today, only a quarter of the state's land area is forested. In central and northern Ohio, farm woodlots make up most of the forested land.
Hardwood deciduous trees predominate. Various types of oak, hickory, and maple are the most abundant trees and are found throughout much of the state. The Ohio buckeye, the state tree, is a common hard-wood. Somewhat less common, though also widely found, are ash, beech, black walnut, and yellow poplar. In the southeast grow southern pines, chiefly shortleaf and Virginia pine. Among the common flowering trees are dogwood and redbud.
Interesting facts about OhioOhio's state tree is the buckeye.