The Mammoth

OCT
2
2026
A multi-day loop race from Mammoth Lakes that circumnavigates a 760,000 year old caldera, crossing alpine lakes, volcanic terrain and Mono Lake tufas. The event offers prize money and uses permitted National Forest routes with a 108 hour cutoff.
Fri 2 Oct 2026

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The Mammoth

The Mammoth is a multi-day loop footrace that starts and finishes in Mammoth Lakes, California. The planned route circumnavigates a 760,000 year old caldera and connects small mountain communities. The course passes alpine lakes, abandoned mines, fall foliage and dense pine forests before moving into the Glass Mountains and high desert terrain. Runners traverse volcanic rock, large Jeffrey pine stands and the tufa towers of Mono Lake, and the route includes summits of Mammoth Mountain with panoramic views from 11,053 feet.

The event operates on permitted National Forest land under special use permission from the Forest Service. Organizers plan to start approximately 250 entrants; there is a pool of reserved spots and a waitlist. If spots become available or an entrant withdraws, the next person on the waitlist may be offered a place and may accept or decline. Early bird pricing is listed as $1595 through February 28.

Prize purses are offered for male and female podiums: $5,000 for first place, $3,000 for second and $2,000 for third. The overall event cutoff is 108 hours. In 2025 the event recorded a 74% finish rate despite storms and over a foot of snow on a summit.

Organizers note that the event may be canceled or postponed for force majeure or if permits are revoked by agencies. Refund and deferral terms vary by withdrawal date and are reduced by the registration platform fee; deferrals are valid for the following year only and nontransferable. Visit the organization's website for the most recent information.

The Mammoth
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