The Allegheny Mountain Range, informally the Alleghenies, is part of the vast Appalachian Mountain Range of the Eastern United States and Canada and posed a significant barrier to land travel in less developed eras. The barrier range has a northeast–southwest orientation and runs for about 400 miles from north-central Pennsylvania, through western Maryland and eastern West Virginia.
The Alleghenies comprise the rugged western-central portion of the Appalachians. They rise to approximately 4,862 feet in northeastern West Virginia. In the east, they are dominated by a high, steep escarpment known as the Allegheny Front. In the west, they slope down into the closely associated Allegheny Plateau, which extends into Ohio and Kentucky. The principal settlements of the Alleghenies are Altoona, State College, and Johnstown, Pennsylvania; and Cumberland, Maryland.