The Unglaciated Allegheny Plateau is located in an arc around southeastern

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the B ...

, into western

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

and a small portion of southwestern

New York State New York, officially the State of New York, is a state in the Northeastern United States. It is often called New York State to distinguish it from its largest city, New York City. With a total area of , New York is the 27th-largest U.S. stat ...

. This area is a

dissected plateau A dissected plateau is a plateau area that has been severely eroded such that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, ...

, characterized by

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

, shale, and many

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...

seams. This is the part of the

Allegheny Plateau The Allegheny Plateau , in the United States, is a large dissected plateau area of the Appalachian Mountains in western and central New York (state), New York, northern and western Pennsylvania, northern and western West Virginia, and eastern Oh ...

that lies outside the continental glaciation of the

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

Geography

One of the most spectacular and scenic areas in this region is located in southeast Ohio, and is known as the

Hocking Hills The Hocking Hills is a deeply dissected area of the Allegheny Plateau in Ohio, primarily in Hocking County, that features cliffs, gorges, rock shelters, and waterfalls. The relatively extreme topography in this area is due to the Blackhand Sand ...

region. This area, similar to but smaller than the

Red River Gorge The Red River Gorge is a canyon system on the Red River in east-central Kentucky. Geologically it is part of the Pottsville Escarpment. The gorge lies within the Daniel Boone National Forest and was subsequently designated the Red River Gorge ...

in the Cumberland Plateau in

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

, features

cliff In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...

s, rock shelters and

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in severa ...

s. The largest city in the Unglaciated Allegheny Plateau is

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylva ...

Rivers

The Ohio River roughly bisects the Unglaciated Allegheny Plateau in generally a north-northeast to south-southwest direction. Other significant rivers in the plateau include the

Muskingum River The Muskingum River (Shawnee: ') is a tributary of the Ohio River, approximately long, in southeastern Ohio in the United States. An important commercial route in the 19th century, it flows generally southward through the eastern hill country o ...

and

Tuscarawas River The Tuscarawas River is a principal tributary of the Muskingum River, 129.9 miles (209 km) long, in northeastern Ohio in the United States. Via the Muskingum and Ohio rivers, it is part of the watershed of the Mississippi River, draining a ...

in Ohio, the

Youghiogheny River The Youghiogheny River , or the Yough (pronounced Yok ) for short, is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 tributary of the Monongahela River in the U.S. ...

and Allegheny River in Pennsylvania, and the

Monongahela River The Monongahela River ( , )—often referred to locally as the Mon ()—is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 river on the Allegheny Plateau in north-cen ...

and

Kanawha River The Kanawha River ( ) is a tributary of the Ohio River, approximately 97 mi (156 km) long, in the U.S. state of West Virginia. The largest inland waterway in West Virginia, its valley has been a significant industrial region of the st ...

in West Virginia. The Kanawha River is formed by the confluence of the New River and the

Gauley River The Gauley River is a river in West Virginia. It merges with the New River to form the Kanawha River, a tributary of the Ohio River. The river features numerous recreational whitewater areas, including those in Gauley River National Recreation Ar ...

. All three rivers are known for their spectacular deep gorges.

References

---- * Allegheny Plateau, Unglaciated Allegheny Plateau, Unglaciated Allegheny Plateau, Unglaciated {{WestVirginia-geo-stub

Geography

Rivers

See also

References