Old Rag Mountain is nestled in the Blue Ridge Mountains in Shenandoah National Park. The trail leading to the top is one of the most popular hikes in Virginia. This is due to the fantastic views, and the scrambling nature of the hike required to reach the summit. The large granitic boulders provide a unique rock climbing experience, and bouldering is be possible along many points in the trail. The summit tops out at 3,284 ft (1,001 m), and affords wonderful views of the Piedmont and Blue Ridge.
The mountain itself is underlain by the Old Rag Granite, a coarse-grained alkali feldspar granite, that crystallized ~1,060 Ma during the Grenville Orogeny. Massive volumes of granitic rock intruded the Earth’s crust during the long-lived Grenville Orogeny, which ultimately formed the supercontinent of Rodinia.
For more information on the geology of Old Rag Mountain consult Paul Hackley’s U.S. Geological Survey Guidebook to the mountain.