The Allegheny Mountain Section consists of broad, rounded ridges separated by broad valleys. The ridges decrease in elevation from south to north and the ridges have no topographic expression at the north end of the section. The ridges occur on the crests of anticlines that have been eroded enough to expose the very resistant rocks that form the crests of the ridges. However, not enough erosion has occurred to breach the anticlines and create parallel ridges such as occur in the Appalachian Mountain Section. The southern parts of these ridges form the highest mountains in Pennsylvania. The valleys are broad, undulating surfaces with shallow to deep stream incision. Relief between the ridge crests and the adjacent valley lowland can be greater than 1,000 feet. Local relief on the broad, valley lowland is generally less than 500 feet. Elevations in the Section range from 775 to 3,213 feet, the highest elevation in Pennsylvania at Mt. Davis.

The Section occurs in southwestern Pennsylvania and includes all of Somerset County, about half of Fayette and Cambria Counties, and parts of Westmoreland, Indiana, Blair, and Bedford Counties.

Scenic routes across this Section Interstate 76 (Pennsylvania Turnpike) from the east boundary of Somerset County to New Stanton; US Route 30 from the east boundary of Somerset County to near Latrobe; and US Route 40 from Maryland to Uniontown. Similar routes across the Section are: Pennsylvania Routes 31 and 653. Routes providing drives the length of the section north from Maryland are: US Route 219 shown on the Map, and Pennsylvania Routes 281 and 381.

Outstanding Geological Scenic Features in the Section include of Bald Knob, Baughman Rocks, Baughman Spring, Bear Rocks, Blue Hole, Blue Hole Spring, Casselman Gorge, Cole Run Falls, Conemaugh Gorge, Conemaugh Water Gap, Elk Rock, Indian Creek Gorge, Jumonville Rocks, Mount Davis, 90-Foot Rocks, Ohiopyle Gorge, Seven-County Scenic View, Suncliff, Vought Rocks, and White Rocks. Also present in the Section are: near 90-foot Rocks - Adams Falls, Grove Run Spring, Flat Rock, Wolf Rocks, and Beam Rocks; near Elk Rock - Cow Rock; near Jumonville Rocks - Fulton Knob and Washington Springs; at Ohiopyle Groge - Ohiopyle Falls and Horseshoe Bend; and near Mt. Davis - High Point Lookout.

State Parks in the Section are: Ohiopyle, Laurel Hill, Kooser, Laurel Summit, Linn Run, Laurel Ridge, Laurel Mountain, and Yellow Creek.

State Forest Natural Areas in the Section are: Mt Davis, Roaring Run, and Charles F. Lewis.

State Forest Picnic Areas in the Section are: Lick Hollow, Mt. Davis, and Babcock.