Marin Ultra Challenge
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Event overview
The Marin Ultra Challenge is a trail running event on March 14, 2026 in the Marin Headlands, Mt. Tamalpais and Muir Woods near Sausalito, California. Distances offered:
- 50 Mile - 50.2 miles; 10,550 ft elevation gain
- 50K - 30.8 miles; ~6,000 ft elevation gain
The event has a field capacity (across distances) of 450 runners. Timing uses disposable chips on the back of bibs and live runner tracking will be provided. Time limits are set at 14.5 hours for the 50 Mile and 10 hours for the 50K.
Course, aid stations and logistics
Both courses start and finish at Rodeo Beach and travel through a mix of fire roads and moderately technical dirt trails, with sections of single-track and redwood canopy. Hiking or trekking poles are permitted. Drop bags are available at Tennessee Valley (Mile 10.5 and Mile 45.8) and Cardiac Aid Station (Mile 19.8 and Mile 29.3 for the 50 Mile). Pacers may join after the second pass through Cardiac Aid Station (mile 29.3).
Aid stations provide a variety of food and drink; Gu gels are restricted at several GGNRA stations. The event is cupless: runners must carry their own bottle or reusable cup; reusable cups will be available for purchase on site. Free parking is available near Rodeo Beach with some walking required from certain lots. Awards include trophies, shoes and cash for top 3 in the 50 Mile and medals and drinking glasses for finishers. Visit the organization's website for the most recent information.