Miwok 100K
Stinson Beach, United States • 2 May 2026
Miwok 100K Ultramarathon
The Miwok 100K is a trail ultramarathon held in the Marin Headlands near Stinson Beach, CA. The course covers 62 miles and includes more than 11,000 feet of elevation gain. The event has a field limit of 400 runners and a time limit of 15 hours and 30 minutes.
The route runs through redwood forests, exposed ridgelines, and coastal cliffs. The course is well marked and features multiple aid stations staffed with professional medical care. Runners are expected to manage steep climbs, exposed sections, and rapidly changing weather, and to meet intermediate cutoff times for safety and permit compliance.
Event formats include the solo 100K and a four person relay. Registration is handled through RunSignUp and has a set opening date in November 2025. Volunteering is part of the event structure; volunteers who contribute at least eight hours receive priority registration for the following year.
The event operates as a cup less, low waste race and partners with organizations that support trail stewardship and environmental responsibility. The organizers also run a Bridge to Trails Initiative begun in 2020 to expand access and representation for Black, Indigenous, and People of Color. Participants receive a finisher award and community support from volunteers and aid station crews. Visit the organization's website for the most recent information.