This is the 67th section of the Appalachian Trail, and it runs 12 miles through Shenandoah National Park from Browns Gap to Simmons Gap. Along the way it passes the Doyles River Overlook, Doyles River Trailhead, Big Flat Mountain, County Line Mountain, the Ivy Creek Overlook, and Pinefield Hut. The trail roughly follows Skyline Drive.
In VA
http://www.tripleblaze.com/trail.php?c=3&i=2377