Mammoth Trail Fest

Mammoth Trailfest (September 25–27, 2026)

Mammoth Trailfest is a multi-day trail running festival held in Mammoth Lakes, California. The event program combines a series of competitive races, community runs, and festival activities over three days.

Race and distance offerings include:

• Mammoth Triple (Dragon's Back Ascent, 50K, 26K)
• Dragon's Back Ascent (summit ascent)
• tenkay (night glow trail)
• 50K
• 26K
• Kid's 1K

Course details and race features vary by event. The 50K is a single-loop mountain course with about 7,000 ft of vertical gain and an average elevation over 9,000 ft; it includes chip timing with on-course splits and a 12 hour cutoff. The 26K is a single-loop course that includes a Mammoth Mountain summit and a 7 hour cutoff. The Dragon's Back Ascent runs from roughly 8,500 ft to over 11,000 ft and includes a summit ceremony; its official purse and cutoff are specified by organizers. The tenkay is a night event that requires headlamps. The Kid's 1K uses the village arch start and finish and awards custom medals.

Entry benefits include event swag, unique finisher medals, post-race food, well stocked aid stations, partner goodies, festival activations, talks, community runs, fan zones, and transport support for specific courses. The event offers reserved or seeded entries for para athletes, elite athletes, and 70+ age group, and operates a waitlist.

Awards and prize money are distributed by category and age group. The event notes wildfire risk and permit dependencies; in the case of event cancellation refunds are not given, and a credit policy applies for participant withdrawal. Participants must be at least 15 years old for the 50K, 26K, and Dragon's Back Ascent; minors require parental consent. Visit the organization's website for the most recent information.