Approximately 700 million years after the Grenville Orogeny, the Iapetus Ocean began to close resulting in the Alleghenian Orogeny when the Old Rag Granite and layers of rock deposited upon it were transported westward and eventually thrust up over the limestone bed around it, forming Old Rag and the Blue Ridge Mountains.

The shorter, most common way is from a parking area in Nethers near the end of Madison County's SR 601, off Virginia State Route 231, at the base of the mountain.

The circuit hike makes use of the Ridge Trail which ascends the mountain 1.6 miles (2.6 km) to the first false summit.

The trail then turns into a rock scramble, which can be strenuous for inexperienced hikers, for 1.1 miles (1.8 km) to the summit and intersection with the Saddle Trail which descends 1.9 miles (3.1 km) down the saddle of the ridge past Byrds Nest #1 shelter and Old Rag shelter to the junction with Weakley Hollow Fire Road.

It boasts splitter cracks, dihedrals, and crystal pinching slabs.The climbs are between 50 and 100 feet (15 and 30 m) in length, and range in difficulty from beginner to expert (5.4- to 5.12+ on the Yosemite Decimal System).