The Big Alta

Lucas Valley-Marinwood, United States • 20-22 Mar 2026

The Big Alta - Marin County trail running weekend, March 20-22, 2026

The Big Alta is a trail running event held in Marinwood, California, centered at the Marinwood Community Center. The event is jointly organized by Freetrail and Daybreak Racing and takes place on trails in Marin County that are used by Freetrail.

Courses include single-loop and point-to-point formats across the county's higher terrain. The routes summit many of the highest points in Marin County and provide extended vistas across the San Francisco Bay Area. The event program mentions live coverage and a finish line experience as part of the race weekend.

Distances offered:

  • 50K single loop
  • 100K point-to-point
  • 28K single loop

Registration for the event closes on Sun, Mar 15. The description focuses on course types, organizers, location, and the scenic nature of the routes within Marin County and the Bay Area. Visit the organization's website for the most recent information.

Race information

100 km
100k
50 km
50k
28 km
28k
Visit the organization's website for the most recent information.
Trail runs nearby

Run the stunning coastal trails around Rodeo Beach at the Golden Gate Trail Run, with distances from 8K to 50K to suit all levels. Expect rugged singletrack, stocked aid stations, generous finisher medals, and unforgettable views.

Trail races from 10K up to 50K plus a free kids 50 yard dash at San Pedro Valley Park in Pacifica on February 21, 2026. Routes run mostly single track with marked ribbons, stocked aid stations and a cupless policy.

Join the Wild Goose Chase at Lime Ridge in Walnut Creek for a map based trail adventure through oaks, quarries, and rock labyrinths. Choose 5K or 10K and navigate an unmarked course to find checkpoints, then enjoy post race treats.

Tackle scenic, hilly trails on Angel Island in Tiburon with 5, 10, and 15 mile courses plus a free 50 yard kids run for ages 6 and under. Expect single track climbs, stunning views, ferry access, medals and stocked aid stations.