The Allegheny Mountain Range —also spelled Alleghany, Allegany and, informally, the Alleghenies—is part of the vast Appalachian Mountain Range of the eastern United States and Canada where it posed a significant barrier to land travel in less technologically advanced eras. It is a barrier range that has a northeast–southwest orientation and runs for about 400 miles (640 km) from north-central Pennsylvania, through western Maryland and eastern West Virginia, to southwestern Virginia.