The trail is currently protected along more than 99% of its course by federal or state land ownership or right-of-way. Annually, more than 4,000 volunteers contribute over 175,000 hours to maintain the it, an effort coordinated largely by the Appalachian Trail Conservancy (ATC), assisted by some thirty trail clubs and multiple partnerships.

Counties crossed: Fannin County → Union County → Lumpkin County → White County → Towns County → Habersham County → Rabun County

Georgia has 76.4 miles (120 km) of the trail, including the southern terminus at Springer Mountain (elevation 3,280 feet (1,000 m), 992 m). An 8.8 mile (12 km) approach trail (not part of the AT) begins at the Amicalola Falls State Park visitor center. The approach trail is often littered with items cast aside by overburdened hikers unprepared for the difficulties of the initial hike. At 4,461 feet (1,360 m), Blood Mountain is the highest point on the trail in Georgia. The AT and approach trail are managed and maintained by the Georgia Appalachian Trail Club.

Counties crossed: Clay County → Macon County → Swain County → Graham County → Swain County → (The following counties are traversed along the Tennessee border) Haywood County → Madison County → Yancey County → Mitchell County → Avery County

North Carolina has 88 miles (142 km) of the trail, not including more than 200 miles (325 km) along the Tennessee border. Altitude ranges from 1,725 to 5,498 feet (525 to 1,676 m).

The trail crosses Bly Gap one-tenth of a mile north of the Georgia state line. The trail further north includes peaks such as Standing Indian Mountain, Mount Albert, and Wayah Bald, followed by a Nantahala Gorge crossing by Wesser Falls and at Nantahala Outdoor Center, and, at the section's north end, is the Fontana Dam Shelter, affectionately known as the Fontana Hilton, known for its view of fjordlike Fontana Lake, comparatively spacious accommodations, water spigots, flush toilets, nearby free hot showers and a one dollar shuttle to an all-you-can-eat buffet. It is also a short distance from a post-office, making it an ideal re-loading location.

Counties crossed: Blount County → Sevier County → Cocke County → Greene County → Unicoi County → Carter County (where it leaves the North Carolina border) → Johnson County → Sullivan County

Tennessee has 293 miles (472 km) of the trail, including more than 200 miles (325 km) along or near the North Carolina border. The section that runs just below the summit of Clingmans Dome in Great Smoky Mountains National Park is the highest point on the trail at 6,625 feet (2,019 m). The trail enters Tennessee from North Carolina atop Doe Knob, on the crest of the Smokies, and exits Tennessee into Virginia atop Holston Mountain.

The first 64 miles (103 km) of the A.T. in Tennessee follows the crest of the Smokies, and is largely shared with North Carolina. In the western Smokies, the trail traverses a young forest that replaced what was once a large highland pasture, most noticeable in areas such as Spence Field, Thunderhead Mountain, and Silers Bald. The trail reaches 6,000 feet (1,800 m) for the first time on the western slope of Mount Buckley (a sub-peak of Clingmans Dome), where it first enters the sub-alpine spruce-fir forest, and comes within a few meters of the summit of Clingmans. The trail crosses US-441 at Newfound Gap and traverses a series of rocky cliffs known as "The Sawteeth" en route to the high ridges of the Eastern Smokies. Here, the trail crosses Mount Chapman and Mount Guyot, and passes one of its most remote shelters at Tricorner Knob before gradually descending.

Just beyond Mount Cammerer, the A.T. exits the Smokies, crossing I-40 into the Cherokee National Forest. After traversing Snowbird Mountain, Max Patch Bald, and Lemon Gap (just south of Del Rio), the trail exits Tennessee atop Bluff Mountain and re-enters again atop Rich Mountain (in Greene County), some 10 miles (16 km) to the northeast.