[1] The Allegheny Front extends for about 180 miles (290 km) southwesterly from south-central Pennsylvania through western Maryland, then divides the eastern panhandle of West Virginia from the rest of that state.

The highest part of the crest of the Allegheny Front is also its southernmost high point, Mount Porte Crayon at 4,770 feet (1,450 m), on the Pendleton/Randolph county line in West Virginia.

The front continues to a point north of the Pennsylvania/Maryland boundary where it is offset about 10 miles (16 km) to the east as it changes from the bold escarpment that characterized it west of Altoona to its more gentle rise in Maryland.

South of the Potomac in West Virginia, the front continues through the Mount Storm area, then passes along the eastern edge of Dolly Sods, a wide plateau of Pottsville conglomerate bedrock at about 4,000 feet (1,200 m) elevation.

Most of the Allegheny Front is capped by a nearly horizontal, erosion-resistant stratum (rock layer) of white Pottsville conglomerate, sometimes where flat with younger Carboniferous strata on top.

[6] The region was then uplifted and folded during the Alleghenian orogeny about 320-250 million years ago, during the Carboniferous[7] and Permian periods, forming the modern Appalachian Mountains as the North American and African tectonic plates collided.

Since the eastern side of the front is drained by Chesapeake Bay stream that drop fairly rapidly through the Ridge and Valley Province to the low-elevation waters of the Great Appalachian Valley, erosion on the eastern slope of this caprock layer has been much more intense than on the western slope, where drainage to low elevations is spread over a greater distance (particularly considering stream meanders) through the Appalachian Plateau to the Ohio River.

The nearly continuous high elevation and clifftop bedrock exposures of the Allegheny Front provide an important corridor of upland habitat in the central Appalachian Mountains.

Many of these windswept cliff-edge outcrops are sparsely vegetated, with occasional one-sided (flagged) red spruce (Picea rubens) trees, and open habitats dominated by various low-growing Appalachian and boreal plant species.

Substantial portions of the Allegheny Front's crest and slopes are parts of a national forest (the Monongahela in West Virginia) or various state, local, or private wildlands parks or preserves.