NOBO and SOBO at a glance
- NOBO
- Northbound, Georgia to Maine on the A.T.
- SOBO
- Southbound, Maine to Georgia on the A.T.
- Katahdin summit closes
- Mid-October
- Baxter State Park
- Thru-hike, any direction
- Whole trail in 12 months or less
- Appalachian Trail Conservancy
Which direction is more popular on the Appalachian Trail?
Northbound, by a wide margin. Most thru-hikers leave Springer Mountain in late winter or spring and follow the season up the range to Maine. The catch is the finish: Baxter State Park closes Katahdin's summit in mid-October, so every NOBO is racing the same deadline from the same small window of start dates.
That is why Georgia gets so crowded in March and early April. Thousands of people start inside the same few weeks, on the same stretch of trail, sharing the same shelters.
What makes a SOBO hike different?
A southbounder starts at Katahdin once Baxter opens for the season, which means walking Maine first: the 100-Mile Wilderness, the unbridged stream crossings and Mahoosuc Notch, at the point when you are least fit for them. Far fewer people go this way.
The reward is quiet. A SOBO walks against the northbound current, so the trail ahead is emptier, and the hike ends in the southern Appalachians in late fall or early winter rather than on top of Katahdin.
What is a flip-flop, and why does the ATC recommend it?
A flip-flop starts somewhere other than either end, walks to one terminus, then jumps back and walks to the other. The Appalachian Trail Conservancy's most common version starts at Harpers Ferry or in Shenandoah National Park in spring, heads north to Katahdin, then returns to the start and walks south to Georgia.
The Conservancy promotes it on purpose. A flip-flop takes pressure off the overcrowded southern end, starts on some of the gentlest terrain on the trail, avoids the cold of the high southern mountains in early spring, and, in the ATC's words, generally offers the longest window of good weather.
Does the direction change whether a hike counts?
No. The Conservancy defines a thru-hike as the whole trail in 12 months or less, whether northbound, southbound or flip-flop, and recognizes every finisher as a 2,000-miler. Its application says it recognizes hikers regardless of sequence, direction or speed.
How do NOBO, SOBO and a flip-flop compare on the Appalachian Trail?
| Direction | Usual start | Usual finish | What it trades |
|---|---|---|---|
| NOBO (northbound) | Springer Mountain, Georgia, in late winter or spring | Katahdin, before Baxter closes the summit in mid-October | The most company, the biggest crowds and a hard deadline |
| SOBO (southbound) | Katahdin, once Baxter opens for the season | Springer Mountain, in late fall or early winter | The hardest terrain first, in exchange for a quieter trail |
| Flip-flop | Mid-trail, often Harpers Ferry or Shenandoah, in spring | Either end, after jumping back to the start | Easier early miles and more weather window, plus one extra trip |
Start points and timing from the Appalachian Trail Conservancy's thru-hiking and flip-flop guidance.
What this means when you're choosing
- The date your finish point closes, then work backward to a start date
- The terrain you meet in your first two weeks, while you are least fit
- How crowded the trail is at your start point in the month you plan to begin
- The transport for a flip-flop's jump, planned before you leave
The common mistake
Picking northbound by default
Most people go NOBO because most people go NOBO, then start in Georgia in March with everyone else. If what you want is weather, solitude or an easier first month, the Conservancy's flip-flop itineraries are built for exactly that, and the finish counts the same.
Common questions
Do NOBO and SOBO only apply to the Appalachian Trail?
No. The shorthand is used on any long north-south trail, including the Pacific Crest and Continental Divide trails, where a NOBO walks from Mexico toward Canada. The A.T. is simply where you hear it most.
Is a flip-flop still a thru-hike?
Yes, if the whole trail is done within 12 months. The Appalachian Trail Conservancy counts flip-flop finishers as thru-hikers and recognizes them as 2,000-milers, the same as anyone who walked end to end.
When should a NOBO start the Appalachian Trail?
Early enough to reach Katahdin before Baxter State Park closes the summit in mid-October, which for a roughly six-month hike means a spring start. The Conservancy's registration platform, ATCamp, exists to help spread those start dates out.
Where this is defined
- 2,000-Milers, Appalachian Trail Conservancy
- Flip-Flop, Appalachian Trail Conservancy
- Thru-Hiker FAQs, Appalachian Trail Conservancy
- 10 Reasons to Consider a Flip-Flop Thru-Hike in 2025, Appalachian Trail Conservancy