The Allegheny Plateau is a major, large-scale landform that extends across much of the northeastern to midwestern United States. Its western, glaciated parts cover much of eastern Ohio. Numerous rounded hills and broad valleys characterize the plateau. The geological formations along the plateau provide evidence of the region's glacial history, with features such as moraines, the accumulation of glacial debris. The plateau's elevations range from 650 to 1,000 feet above sea level. The area is densely forested with maple, beech, oak and various hardwoods. Dominant fauna include white-tailed deer, raccoon, foxes, cottontail rabbits and eastern chipmunks. The annual precipitation averages around 35 or 40 inches per year, with no marked rainy or dry seasons.
Over one-half of Lake Erie's shoreline is within Ohio, including Sandusky Bay and Ohio's islands. In total, that puts Ohio's lakefront shoreline at 312 miles. Lake Erie is the southernmost of the Great Lakes, with the shallowest waters, making it the warmest of all the lakes, a great advantage for water recreation. The lake's relatively warm temperatures also make it an excellent habitat for mollusks, plankton, algae and other bottom organisms, as well as a great diversity of fish species. Ohio has a relatively high degree of development along the lake's shoreline; there are no large remaining expanses of forest or beach land. Instead, cottages, resort development and cities line much of the shore.
The Ohio River runs along Ohio's southern and eastern borders. The river forms where the Allegheny and Monongahela rivers join together, in Pittsburgh, Pennsylvania. It runs a total of 981 miles, merging into the Mississippi River at Cairo, Illinois. Two times in the 19th century, the U.S. Army Corps of Engineers worked to improve transport conditions on the river, building lock and dam systems and removing snags and sandbars along the river's course. As a result, the Ohio River serves as an important commercial waterway, responsible for the passage of boats carrying 150 million tons of cargo every year, as of 2010. Historically, the river has long served as a dividing line between different territories. In the colonial period, the river by treaty separated the English settlers south of the river from the Native American settlements to the north, in present-day Ohio.
