Mammoth Lakes, California · Trail
Official site ↗The Mammoth
A 218-mile single loop of the Eastern Sierra from the Village at Mammoth, California, with 31,091 feet of climbing, 21 aid stations and a 109-hour limit.
Friday, October 2, 2026 at 9:00 AM GMT-7
The race states that its 2026 route is still pending Forest Service approval, and that it will update the cut-offs once the final course and aid stations are set.
Registration is open through August 31, 2026.
Distances
- Distance
- 218 mi (351 km)
- Vert gain
- 31,091 ft (9,500 m)
- Cutoff
- 109 hr
WSER 2027 qualifier (sub-100:00)
| Distance | Vert gain | Cutoff | Notes |
|---|---|---|---|
| 218 mi (351 km) | 31,091 ft (9,500 m) | 109 hr | WSER 2027 qualifier (sub-100:00) |
About
The Mammoth, which the race also writes as the MAMMOTH 200, runs a single 218-mile loop through the Eastern Sierra from the Village at Mammoth in California. It climbs and drops 31,091 feet, tops out at 11,053 feet and averages a little over 8,000, and gives runners 109 hours to get round. There are 21 aid stations, 17 of them fully stocked, five sleep stations, and about 15 miles between the two furthest apart.
The 2026 edition starts at 9:00 a.m. on Friday, October 2 and closes at 10:00 p.m. on Tuesday, October 6. Entry is straight sign-up on UltraSignup with no lottery and no qualifying standard, opening in early January and closing on August 31; the 2026 race sold most of its places within a quarter of an hour of opening. A finish under 100 hours is a Western States 100 qualifier. The race is put on by Eastern Sierra Running, the team behind the Mammoth Trailfest weekend in September.
Course
A single 218-mile loop out of the Village at Mammoth, elevation 8,050 feet, on a mix of singletrack, doubletrack and about 7 percent road. The race states 31,091 feet of gain and the same again in descent, a maximum altitude of 11,053 feet and an average of 8,053. Twenty-one aid stations, four of them water only, and five sleep stations, with roughly 15 miles between the two that sit furthest apart.
How to register
Entry is first-come sign-up on UltraSignup. The race states that it has no qualifying process: runners are expected to judge their own readiness for a 200-mile race before entering. The 2026 window opens in early January at early-bird pricing and closes on August 31, and the race reported being three quarters sold out within fifteen minutes of opening. A payment plan is offered on a first-come basis. The race publishes no field cap.