The Big Alta

The Big Alta

The Big Alta is a three day trail running event in Marin County, California, produced by Daybreak Racing and Freetrail. It takes place March 19–21, 2027 and offers multiple race distance options across a weekend format.

Race distances include:

• 50K single loop course
• 100K new point to point course
• 28K single loop course

Courses rise to many of Marin County’s highest points and include landmarks such as Loma Alta and Big Rock Ridge. The routes provide wide views across the San Francisco Bay Area and follow established trails in the region.

The event is staged at Marinwood Community Center and Park in San Rafael. Registration is handled through UltraSignup; the organizers state each race day is limited to 300 runners, there is no lottery, and a waitlist is activated once a race fills. Registration fee tiers are listed by the organizer; certain shuttle services and swag items require additional fees. The 100K requires runners to carry an uploaded .gpx file on a navigation device during the race.

Event services listed by the organizers include chip timing with live splits, staffed aid stations, professional medical support, shuttle buses, post race food and beverages, custom finisher awards, and professional photography. Friendly leashed dogs are allowed at the staging area but are not permitted on the course. The event includes a land acknowledgement for the traditional lands of the Coast Miwok people. Visit the organization's website for the most recent information.