The Mammoth
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THE MAMMOTH
THE MAMMOTH is an ultramarathon held in Mammoth Lakes, California, organized by trailfest. The route is a loop that starts and finishes in Mammoth Lakes and circumnavigates a 760,000-year-old caldera. The course passes alpine lakes, abandoned mines, fall foliage, dense pine forests, the Glass Mountains, volcanic rock fields, and the Tufa towers of Mono Lake. Runners gain summits of Mammoth Mountain with views from 11,053 feet and traverse high desert terrain and large Jeffrey pine stands.
The event operates on permitted National Forest land and uses authorized facilities under special use permission from the Forest Service. Volunteer positions are available; volunteers receive exclusive swag and race credits. Registration is managed through the event listing; registration closes August 31, 2026. Early bird pricing was $1595 through February 28, 2026, and the currently listed price is $1894.23.
The event schedule includes a mandatory check-in in the Village Plaza on October 1, race day activities on October 2 with mandatory Spot Tracker pickup and gear check, first finishers expected on October 4, an awards ceremony on October 5 at the start/finish area, a village cutoff day on October 6 with a race cutoff of 109 hours, and final drop bag pickup by October 7 at the Grand Sierra Lodge Whitney Room. Prize money is offered to male and female podium finishers at specified amounts for first through third place.
Refunds and deferral options follow a tiered policy based on withdrawal date; refunds are reduced by the ultrasignup fee. Visit the organization's website for the most recent information.
