The Big Alta
Lucas Valley-Marinwood, United States • 20-22 Mar 2026
The Big Alta : March 20-22, 2026
The Big Alta is a three-day trail running event in Marin County, California, produced by Daybreak Racing and Freetrail. The event is staged at Marinwood Community Center & Park in San Rafael and includes courses that summit many of Marin County's highest points and offer views across the San Francisco Bay Area. The event offers three race distances:
- 50K - single loop
- 100K - new point-to-point
- 28K - single loop
Logistics and race services
Registration is handled through Ultrasignup. Each race day is limited to 300 runners. Race services include chip timing, live on-course splits and results, staffed aid stations, professional medical support, shuttle buses, post-race food and beverages, and custom finisher awards. Podium prize money will be awarded to top finishers - amounts to be determined.
Practical details: bib pickup is available at a Mill Valley shop and at the Marinwood staging area on selected days; 100K runners must bring drop bags and cannot pick up bibs on race morning. A shuttle bus option to the 100K start is available for a fee. Participant parking is curbside along Miller Creek Road. Friendly leashed dogs are allowed at the staging area but not on the course. An inclement weather gear requirement may be activated and specifies items such as a running pack, rain jacket, smartphone, emergency blanket, whistle, ID, nutrition and fluids. Visit the organization's website for the most recent information.