Marin Ultra Challenge
Always double-check with the organizer's website! This page may contain affiliate links.
Event overview
The Marin Ultra Challenge is a trail race on March 14, 2026 in the Marin Headlands, Mt. Tamalpais and Muir Woods area near Sausalito, California. The event offers two distances:
- 50 Mile (50.2 miles, 10,550 ft elevation gain)
- 50K (30.8 miles, ~6,000 ft elevation gain)
The event has a total capacity of 450 runners across both distances. Timing uses disposable chips on the back of each bib and will include live runner tracking. 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. Overall and age-group awards are given, and cash prizes are offered for the top three finishers in the 50 Mile.
Course and logistics
Courses run primarily on moderately technical dirt trails and non-technical fire roads, with sections of tight single-track and redwood canopy. Hiking or trekking poles are permitted. The route starts and finishes at Rodeo Beach and includes notable features such as coastal viewpoints, Dipsea Trail sections, Willow Camp climbs, and stretches through Muir Woods.
Aid stations supply a range of food and drink options; Gu gels are not permitted at aid stations located on Golden Gate National Recreation Area property. The event is cupless, so each runner must carry a bottle or reusable cup (HydraPak cups available for purchase). Drop bags are staged at Tennessee Valley and Cardiac aid stations (specific mile locations provided), and printable GPX course files and maps are available. Free parking is available in nearby lots and pullouts; dogs are not allowed on the course but are permitted on leash at Rodeo Beach. Visit the organization's website for the most recent information.