Allegheny Mountains

Mountain range over 800 km/500 mi long extending from Pennsylvania to Virginia, rising to more than 1,500 m/4,900 ft and averaging 750 m/2,500 ft. Part of the Appalachian Mountains system, the Alleghenies are rich in hardwood timber and bituminous coal, and also contain iron ore, natural gas, clay, and petroleum. The mountains initially hindered western migration, with the first settlement to the west being Marietta in 1788.

The Alleghenies lie within the two westernmost bands of the Appalachian Mountian system. Allegheny Mountain, along the West Virginia–Virginia border, is the westernmost ridge of the Valley and Ridge Province, and is part of the Allegheny Front. The balance of the Alleghenies lies across the eastern edge of the Allegheny Plateau, the northern section of the Appalachian Plateau. The Allegheny Plateau, covering a large area reaching from south of the Mohawk River in New York to south West Virginia and into Ohio and Kentucky, also includes the Catskill and Pocono mountains.