272 Miles in Less Than 4 Days: William Peterson Sets New Long Trail FKT

On the morning of September 1, William “Sisyphus” Peterson reached the Vermont-Massachsetts border and set a new Fastest Known Time (FKT) on the Long Trail. Peterson completed the route in 3 days, 21 hours, and 10 minutes, breaking John Kelly’s previous record of 4 days, 4 hours, 25 minutes, 50 seconds. Stretching 272 miles (437.74 km) through the state of Vermont, the Long Trail climbs 67,000 feet (20,421 m).

Peterson ran a supported FKT, meaning that he had outside assistance along the way. In an Instagram post after the record he wrote, “I feel truly privileged to be a part of this group as the runner. My pacers and crew were flawless.”

Averaging close to 70 miles per day, Will started behind his pace goal but quickly caught up.  By the time he reached Mount Killington, he boasted a two-hour lead. Peterson told me he realized he was on pace for the record with about 100 miles to go. The possibility of a sub-four hour time crossed his mind but it wasn’t until he hit Stratton, VT ( with 42 miles remaining) that the reality set in. 

Peterson (white shirt) embraces a member of his crew at the southern terminus of the Long Trail. Photo via Mike Tidd

While many people attempting FKTs enter the sport from ultra-running, Peterson comes at it from a thru-hiker’s perspective.  After hiking the AT in 2019, he found himself looking for more opportunities for backpacking trips and adventure. As a medical student, the ability to take multiple weeks or months off for a thru-hike wasn’t feasible, so he turned to FKTs to “condense the backpacking trip into a few days.”

Other types of FKTs include self-supported and unsupported. Self-supported involves carrying all your gear and resupplying using boxes you have pre-mailed, food caches, or shopping. An unsupported FKT involves carrying all your gear and food for the trip without resupplying. Peterson also currently holds the unsupported FKT for the Long Trail which he set in July 2023 at 4 days, 11 hours, 34 minutes.

As one of Fastest Known Time’s premier routes, Peterson had to announce his attempt in advance and track it live. Premier routes are high-visibility routes such as the Long Trail, the Appalachian Trail, the John Muir Trail, and several other famous backpacking trails.  You can see Peterson’s tracked data here.