The Appalachian National Scenic Trail spans 14 U.S. states over its roughly : Georgia, North Carolina, Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine. The southern end is at Springer Mountain, Georgia, and it follows the ridgeline of the Appalachian Mountains, crossing many of its highest peaks and running almost continuously through wilderness before reaching the northern end at Mount Katahdin, Maine.

The trail is currently protected along more than 99 percent 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 trail, an effort coordinated largely by the Appalachian Trail Conservancy (ATC), assisted by some thirty trail clubs and multiple partnerships.

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

Georgia has of the trail, including the southern terminus at Springer Mountain (elevation ). An approach trail (not part of the AT) begins at the Amicalola Falls State Park visitor center. At , 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.

See: Georgia Peaks on the Appalachian Trail

North Carolina 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 of the trail, not including more than along the Tennessee border. Altitude ranges from .

The trail crosses Bly Gap one-tenth of a mile north of the Georgia state line.http://www.aldha.org/company/ga-tn10.pdf 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.

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 three dollar shuttle into Fontana Dam, North Carolina.

Tennessee 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 of the trail, including more than along or near the North Carolina border. The section that runs just below the summit of Kuwohi (formerly Clingmans Dome) in Great Smoky Mountains National Park is the highest point on the trail at . The trail enters Tennessee from North Carolina atop Doe Knob and exits Tennessee into Virginia atop Holston Mountain.

The first of the A.T. in Tennessee follow the crest of the Smokies, and are 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 for the first time on the western slope of Mount Buckley, a sub-peak of Kuwohi, where it first enters the sub-alpine spruce-fir forest, and comes within a few meters of the summit of Kuwohi.

The trail crosses U.S. Route 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 Interstate 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 to the northeast.

After traversing the Bald Mountains, the Appalachian Trail crosses the Nolichucky River and enters the Unakas, gradually ascending to the Roan Highlands near the town of Roan Mountain in Carter County. Atop Roan High Knob, the A.T. again eclipses 6,000 feet (approximately ), and passes the highest shelter along the entire trail. After crossing Grassy Ridge, which is the longest stretch of grassy bald in the Appalachians, the trail descends to the Laurel Fork Valley, where it turns west away from the state boundary.

Just beyond White Rocks Mountain, the trail passes through Hampton, Tennessee, before turning north again. At Watauga Lake at the TVA Watauga Dam, the trail turns northeast, crossing Iron Mountain before turning briefly to the northwest at the Carter County-Johnson County line. After passing over Cross Mountain, the trail again turns northeast and ascends Holston Mountain en route to Virginia.

Virginia Counties crossed: Washington County → Smyth County → Grayson County → Wythe County → Bland County → Tazewell County → Giles County Briefly joins the West Virginia border here → Craig County → Montgomery County → Roanoke County → Botetourt County → Bedford County → Rockbridge County → Amherst County → Nelson County → Augusta County → Albemarle County → Rockingham County → Greene County → Page County → Rappahannock County→ Warren County → Fauquier County → Clarke County → (rejoins the West Virginia Border here) Loudoun County

Virginia has the most mileage of the trail of any state with of the trail (one-fourth of the entire trail), including more than along the West Virginia border. With the climate, and the timing of northbound thru-hikers, this section is wet and challenging because of the spring thaw and heavy spring rainfall.

Substantial portions of the trail closely parallel Skyline Drive in Shenandoah National Park and, further south, the Blue Ridge Parkway. The Appalachian Trail Conservancy considers to be excellent for beginning hikers a well-maintained section of the trail that the Civilian Conservation Corps constructed in Shenandoah National Park and whose climbs rarely exceed .

McAfee Knob is affectionately known as "the most photographed spot on the A.T.".Metz, Casey (May/June 2007), "Appalachian Trail Tidbit". National Geographic Traveler. 24 (4):159 McAfee Knob is part of what is known as Virginia's Triple Crown. The three iconic peaks that make up the Triple Crown are McAfee Knob, Dragon's Tooth, and Tinker Cliffs. These three peaks are located near Roanoke, VA. Hikes to each of the overlooks can be completed individually as day hikes or in one trip as an approximately 35 mile backpacking trip.

The plant life on Virginia's section of the trail includes thickly-growing wild blueberry bushes. The bushes are especially numerous along the trail's central sections, through the Shenandoah National Park, and its northern sections. The blueberries ripen in late summer, offering hikers a plentifully available food source.

In 1989, Hurricane Hugo damaged over 300 miles of the Appalachian Trail in Virginia.Curtis, Wayne (June 1990). "Hugo and the trial". 18 (4):16 Three weeks of rain uprooted thousands of trees in what Mike Dawson of the Appalachian Trail Conference called "the worst break in the continuous footpath since it was declared open from Maine to Georgia in August 1937." Due to responsive and prepared local trail clubs, all but six miles of the trails were re-opened within a month.

The annual "Trail Days" festival held in Damascus has become the largest single gathering of Appalachian Trail hikers anywhere.Collier, Christopher Percy (May 12, 2006), "Good Times at a Backpackers' Paradise". New York Times. 155 (53577):D1-D5

West Virginia

Counties crossed: Monroe County (while sharing the trail with Virginia in the south → Jefferson County (while sharing the trail and briefly entering the state.)

West Virginia has of the trail, not including about along the Virginia border. The trail passes through the town of Harpers Ferry, headquarters of the Appalachian Trail Conservancy. Harpers Ferry is considered the "psychological midpoint" of the AT. The actual midpoint is just west of Pine Grove Furnace State Park in Pennsylvania.

Maryland Counties crossed: Washington County → Frederick County

Maryland has of the trail, ranging in elevation from . Most of the trail runs along the ridge line of South Mountain in South Mountain State Park Hikers are required to stay at designated shelters and campsites, no camping off-trail. Some hikers choose to hike Maryland in a single day, usually starting just before dawn and ending at dusk. This is known as the Maryland Challenge.

The Challenge is especially popular among thru-hikers due to the endurance built up by the time one reaches Maryland from either terminus. A variation of this challenge, known as the Four State Challenge, involves hiking between the ridge line straddling Virginia and West Virginia all the way to or from Pennsylvania in 24 hours, thus hiking in four states in one day. The Four State Challenge requires a hike of approximately , most of which are in Maryland.

The state contains the Ensign Cowell shelter, and the Rocky Run Shelters near Boonsboro. The older log structure was built by the CCC in 1940.

Another stop is the Dahlgren Campground. Hikers can stop here for the night and have free showers. The trail passes close to the eastern edge of Greenbrier State Park. The trail also goes through Pen Mar Park, which is just north of High Rock, which offers views and is a former hang-gliding site.

On March 15, 2015, a hiker was killed near the Ed Garvey shelter in the southern part of the state's portion of the trail when a large tree fell on him.

Pennsylvania

Counties crossed: Franklin County → Cumberland County → Perry County → Dauphin County → Lebanon County → Schuylkill County → Berks County → Lehigh County → Carbon County → Northampton County → Monroe County

Pennsylvania has of the trail, extending from the Pennsylvania-Maryland border at Pen Mar, a tiny town straddling the state line, to the Delaware Water Gap, at the Pennsylvania-New Jersey line. The Susquehanna River is generally considered the dividing line between the northern and southern sections of the Pennsylvania AT. The AT crosses the Susquehanna via the Clarks Ferry Bridge, near Duncannon.

In the southern half of Pennsylvania, the AT passes through Caledonia State Park, Michaux State Forest, and Pine Grove Furnace State Park. In 1935, the midpoint of the AT was at Center Point Knob. It is currently in Pine Grove Furnace State Park and marked by a "Midpoint" sign.

These areas in south central Pennsylvania are the northernmost portions of the Blue Ridge Mountains, which are geologically distinct from the Ridge and Valley section further north. The two parts are separated by the broad Cumberland Valley, where the trail has a change of scenery, crossing many farms and large highways. There is no camping allowed in the stretch between Alec Kennedy and Darlington shelters.

In the northern half of Pennsylvania, the AT climbs back up into the mountains and passes through St. Anthony's Wilderness, which is the second largest roadless area in Pennsylvania and home to several coal mining ghost towns, such as Yellow Springs and Rausch Gap. Trail towns that are common stops with thru-hikers are Boiling Springs, Duncannon, Port Clinton, Palmerton, Wind Gap, and Delaware Water Gap. Northeast of the Schuylkill River, the trail runs along the top of the Blue Mountain ridge.

Just before entering New Jersey, the Blue Mountain ridge becomes the Kittatinny Ridge. The Trail between Swatara Gap and the Susquehanna river was relocated off of Blue Mountain onto Second Mountain and Peter's Mountain in the early 1950s due to expansion of the Fort Indiantown Gap military reservation.