Old Rag Mountain, a three thousand two hundred eighty-four-foot peak near Sperryville, Virginia, is Shenandoah National Park’s most popular hiking destination and is distinguished by its exposed, rocky summit. Its appearance reflects a complex geologic history: Old Rag Granite formed about a billion years ago, later overlain by greenstone from basaltic magma and by marine sediments that became sandstone, quartzite, and limestone, before uplift helped shape the mountain and the Blue Ridge. The mountain is also a notable mid-Atlantic climbing area with extensive granite exposures. Heavy visitation has brought access changes, including new parking arrangements and day-use ticket requirements to reduce crowding and resource damage.