The Big Alta
Lucas Valley-Marinwood, United States • 20-22 Mar 2026
Event
The Big Alta is a three-day trail running event produced by Daybreak Racing and Freetrail in Marin County, California, held March 20-22, 2026. The courses summit multiple high points in Marin and feature views across the San Francisco Bay Area. The event name references local landmarks Loma Alta and Big Rock Ridge. The organizers include a land acknowledgement for the Coast Miwok people.
Distances
- 50K single loop
- 100K point-to-point
- 28K single loop
Logistics and registration
The event is staged at Marinwood Community Center & Park (775 Miller Creek Road, San Rafael, CA). Parking for participants is curbside along Miller Creek Road; the Marinwood Park lot is reserved for the public and officials. Registration is handled through UltraSignup. Each race day has a capacity limit of 300 runners; there is no lottery and a waitlist is used if a race fills. The 100K offers an optional shuttle bus to the start for a fee; runners are not permitted to leave vehicles at the 100K start due to National Park Service rules. The registration fee covers a professionally organized race, a fully marked course, chip timing with live splits and results, staffed aid stations, professional medical support, restroom facilities, shuttle buses, post-race food and beverages, custom finisher awards, professional photography, and required permitting. Awards, a raffle and podium prize money are part of the event program. Visit the organization's website for the most recent information.