Allegheny Mountains

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The Allegheny Mountains are a part of the Appalachian mountain range of the eastern United States. The Alleghenies have a northeast-southwest orientiation and run through West-Central Pennsylvania, western Maryland and eastern West Virginia.

The eastern edge of the Allegheny Mountains is marked by the Allegheny Front, which has an elevational change of up to three thousand feet. Absolute elevations of the Alleghenies reach nearly five thousand feet, with the highest elevations in the southern part of the range. The highest point in the Allegheny Mountains is Spruce Knob, located in Pendleton County, West Virginia. Other notable Allegheny highpoints include Thorny Flat, Bald Knob, and Mount Porte Crayon, all in West Virginia.

To the West, the Allegheny Mountains grade down into the dissected Appalachian Plateaus -- the Allegheny Plateau to the North and the Cumberland Plateau to the South. To the East of the Allegheny Mountains lies the Ridge and Valley Province of the Appalachians, which extends eastward to the Blue Ridge in Virginia.

Much of the Monongahela National Forest in West Virginia is in the Allegheny Mountains. These mountains also include the Dolly Sods Wilderness, Laurel Fork Wilderness, and Cranberry Wilderness. The Alleghenies of West Virginia are also famous for their forests of Red Spruce, Balsam Fir, and Mountain Ash, trees typically found much further north.

The bedrock of the Alleghenies is mostly sandstone and metamorphosed sandstone, quartzite, which is extremely resistant to weathering. Prominent beds of resistant conglomerate can be found in some areas, such as the Dolly Sods area. When it weathers, it leaves behind a pure white quartzite gravel. The rock of the Alleghenies were formed during the Alleghenian orogeny.

Because of intense freeze-thaw cycles in the higher Alleghenies, there is little native bedrock exposed in most areas. The ground surface usually rests on a massive jumble of sandstone rocks, with air space between them, that are gradually moving down-slope. The crest of the Allegheny Front is an exception, where high bluffs are often exposed, revealing an exceptional view.

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