Map of the Allegheny plateau. The gray line divides the glaciated (northern) and unglaciated (southern) sections of the plateau.
The
Allegheny Plateau is a large
dissected plateau area in western and central
New York, northern and western
Pennsylvania, northern
West Virginia, and eastern
Ohio. It is divided into the
unglaciated Allegheny Plateau and the
glaciated Allegheny Plateau.
The plateau extends southward into western
West Virginia, eastern
Kentucky and
Tennessee where it is instead called the
Cumberland Plateau.
The plateau terminates in the east at the
Allegheny Mountains, which are the highest ridges just west of the
Allegheny Front. The front extends from central Pennsylvania into eastern West Virginia.
The plateau is bordered on the west by glacial till plains in the north, generally north of the
Ohio River, and the
Bluegrass region in the south, generally south of the Ohio River.
Elevations vary greatly. In the glaciated Allegheny Plateau, relief may only reach one hundred feet or less. In the unglaciated Allegheny Plateau in southeastern Ohio and westernmost West Virginia, relief is typically in the range of two hundred to four hundred feet. Absolute highest elevations in this area are often in the range of . By the Allegheny Front, however, elevations may reach well over , with relief of up to .
One of the more notable geologic areas within the Allegheny Plateau is the
Hocking Hills region of southeast
Ohio.
Geology and physiography
Canisteo River Valley from
Pinnacle State Park.
Glaciation in this area of the plateau removed the sharp relief that is seen in unglaciated areas of the plateau. The line of the distant peaks approximates the level of a
peneplain that was uplifted to form the plateau.
The Allegheny Plateau is a
physiographic section of the larger
Appalachian Plateau province, which in turn is part of the larger
Appalachian physiographic division.
