A linear ridge running northeast to southwest in Grant and Pendleton counties, North Fork Mountain extends 34 miles from North Fork Gap to Snowy Mountain (Dry Run) Gap in West Virginia. The mountain runs parallel to the North Fork of the South Branch. It represents the southeast limb of the Wills Mountain Anticline, a large geologic structure that extends northward into central Pennsylvania. At North Fork Mountain southeast-dipping, Silurianage Tuscarora sandstone forms prominent northwest-facing cliffs, some more than 100 feet high, along the mountain crest. These cliffs offer some of the most spectacular scenery in West Virginia. Elevations increase southward, from about 3,120 feet at Chimney Top to about 4,500 feet at Kile and Panther knobs, near the Virginia border south of Circleville. The appearance of this mountain from the west, visible along its entire length from nearby State Route 28, is perhaps the most distinctive of any in the state. The North Fork Mountain Trail extends 24 miles northward from U.S. 33, offering majestic vistas of Germany Valley and North Fork Valley and the Allegheny Front. There are 360-degree views from Chimney Top.

By purchase and conservation easements, the Nature Conservancy has protected several thousand acres on the mountain's southern reaches. Several preserves harbor rare plant and animal communities. Pike Knob (4,280 feet elevation) features grass balds and a virgin red pine forest, this species' southernmost natural occurrence. On Panther Knob are a rare dwarf pitch pine woodland and a virgin red spruce forest. Many globally rare plants are present in these unique habitats, cold and dry, which result from high elevations, windswept sandstone cliffs, and the area's location in a "rain shadow" of low annual precipitation.