Miwok 100K

Stinson Beach, United States • 2 May 2026

Event overview

The Miwok 100K is a trail ultramarathon held on the Marin County coast in California with a Start/Finish in the town of Stinson Beach. The event includes these race formats:

  • 100K
  • 4-person Team Relay

The May 3, 2025 Miwok 100K is listed as a UTMB 2026 Index Race at the 100K level and is a Western States 100 (WS100) 2026 qualifier. Stinson Beach is described as being less than an hour from San Francisco and offers local cafés, a small market, and lodging near Mount Tamalpais.

Course, support and sustainability

The course uses single-track trails and dirt roads with about one mile of paved road and totals approximately 11,800 feet of elevation gain. Course marking is described as strong, and the race provides volunteer support and professional medical coverage at all aid stations.

The event reports long-term sustainability practices, including recycling, food composting, waste minimization, and a cup-less policy since 2013. Leftover food is donated to a local shelter. The race is a member of 1% For The Planet and Leave No Trace and works with a program to TerraCycle race nutrition packaging. Organizers list a Diversity Initiative launched in 2020 and name several community organizations they support or have donated to. Visit the organization's website for the most recent information.

Race information

100 km
11800 m+
100k
Visit the organization's website for the most recent information.
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