Marin Ultra Challenge
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About the race
The Marin Ultra Challenge is a trail running event on March 13, 2027 in Sausalito, CA, organized by Inside Trail Racing. The event uses trails in the Marin Headlands, Muir Woods, and Mount Tamalpais State Park and begins at Rodeo Beach.
The courses feature varied terrain including exposed fire roads with coastal and inland views, tight technical single-track under redwood canopies, significant climbing, and sweeping descents. The 50 Mile route has about 11,000 feet of elevation gain. There is very little trail overlap between course sections.
Distances:
- 50 Mile approximately 11,000 feet elevation gain
- 50K through Marin Headlands, Mt Tamalpais, and Muir Woods
Race capacity is 500 entrants across both distances. Time limits are 14 hours for the 50 Mile and 10 hours for the 50K; all runners must be off course by the designated cutoff. Aid stations offer a range of foods and beverages including electrolyte mixes, fruit, gels, sandwiches, and basic first aid; some GGNRA aid stations restrict packaged gels. Runners are encouraged to carry at least one 20 oz bottle. Drop bags and headlamps are available recommendations for runners expecting to be on course after dark; drop bag locations are listed for Tennessee Valley and Cardiac aid stations.
Awards include cash prizes for the top three 50 Mile finishers, finishers’ medals, trophies, age-group medals, and special awards for the dead last finisher. Volunteers receive event shirts, food, and credits toward future events. Visit the organization's website for the most recent information.
