Allegheny Mountains
![](/Images/godic/202412/18/View_from_the_observation_tower_atop_of_Spruce_Knob_WV0139.jpg")
![](/Images/godic/202412/18/Cumberlandplateaumap0139.png")
![The George Washington and Jefferson National Forests lie on the eastern slopes of the Alleghenies. The Monongahela NF lies within the central Alleghenies.](/Images/godic/202412/18/Va_nationalforests0140.png")
![Detail of a French map of 1671. The Alleghenies are in the lower center portion.](/Images/godic/202412/18/Carte-de-L-AMERICQVE-1671-clip0140.png")
The Allegheny Mountain Range /ælᵻˈɡeɪni/—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.