Marin Ultra Challenge
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Marin Ultra Challenge - March 14, 2026
The Marin Ultra Challenge is a trail ultramarathon held in the Marin Headlands, Mt. Tamalpais, Muir Woods and surrounding areas near Sausalito, California. The event offers two distances:
- 50 Mile - 50.2 miles with 10,550 feet of elevation gain
- 50K - 30.8 miles with approximately 6,000 feet of elevation gain
The race capacity is up to 450 runners across both distances. Live runner tracking will be used and disposable timing chips are attached to bibs. Time limits are 14.5 hours for the 50 Mile and 10 hours for the 50K; all runners must be off course by 8:30 PM.
Course and race logistics
Courses start and finish at Rodeo Beach and traverse coastal and inland trails including fire roads and technical single-track. Notable sections include views from the Headlands, the Dipsea Trail, Willow Camp climbs, Cardiac Hill, Muir Beach, Stinson Beach, Muir Woods, Dias Ridge, and Middle Green Gulch. The route is marked with colored ribbon and signs; blue ribbons indicate wrong-way trails.
Aid stations provide a range of food and hydration options; Gu gels are not allowed at certain GGNRA aid stations. The event is cupless - runners must carry their own cup or bottle; a 20 oz bottle is recommended. Drop bags are available at Tennessee Valley and Cardiac aid stations. Trekking poles are permitted. Free parking is available near Rodeo Beach; the walk from the Marine Mammal Center lot is about 1/3 mile. Visit the organization's website for the most recent information.
