Trail Running calendar near Castro Valley 2026-2027

Run by the Sea at Wilder Ranch State Park on October 4, 2026 offers a Half Marathon, 12K and 4K run/walk along mostly flat packed dirt trails with coastal bluff and Monterey Bay views. Organized by the Santa Cruz Track Club; proceeds benefi..

Test your endurance at Lake Merced in San Francisco with a scenic 4.5 mile loop course. Choose between a standard run or tackle ultra marathon distances including the 50K and 50 mile events.

A trail race at Almaden Quicksilver County Park with distances from 5K to 50K. Courses are out-and-back, marked with colored ribbons, include aid stations and toilets, and the longer races reach Bald Mountain and Mt. Umunhum.

A roughly 12 mile loop from Mitchell Canyon to the Mount Diablo summit and back, with about 4,200 feet of elevation change. The course includes steep climbs via Eagle Peak and Bald Ridge and a five hour cutoff.

A multi-distance trail event at Lake Sonoma on October 17-18, 2026 offering 100 Mile, 50 Mile, marathon and 4-person relays on singletrack with substantial elevation and on-site camping.

A trail running event at Mount Diablo in Walnut Creek on October 17, 2026 offering 30K, Half Marathon, 10K and 5K courses on hilly trails where mud and creek crossings are possible.

Run through the lush single track trails and babbling streams of Bothe Napa Valley State Park. This exclusive event offers marathon, half marathon, and 10K distances for a maximum of 300 participants.

A trail race in Redwood Regional Park and nearby EBMUD trails offering 35K, half marathon, and 10K distances, cupless aid stations, and limited field size amid tall coast redwoods.

Celebrate Halloween with a trail race through San Jose Hellyer County Park. Choose from distances including 5K 10K Half Marathon and Marathon with costume prizes and certified courses.

Trail races in Almaden Quicksilver Park from 5K to 50K over hilly dirt roads and single-track, with two staffed aid stations, drop-bag service for longer distances, and a finisher medal for all participants.

Support student programs and the Oakland Tech Cross Country team at Joaquin Miller Park. Choose between a five kilometer trail race or a one mile fun run through the redwood trees.

A trail event at Huddart Park on November 7, 2026, featuring multiple distances from a youth dash to a 6 Hour Challenge, single-track redwood trails, aid stations, chip timing, and a post-race pancake breakfast.

Lake Chabot Trail Run in Castro Valley on November 7, 2026 offers distances from an 8K to a 50K plus a free kids 50 yd dash. The marked trail circles the reservoir with aid stations every 4 to 5 miles and a cupless policy.

Mt. Tam Trail Run offers 10K, half, 30K and 50K trail races at Mt. Tamalpais State Park with technical singletrack, chip timing, cupless aid stations, and a 500 runner capacity.

A November trail event at Rancho Cañada del Oro offering distances from 5K to 50K, with steep climbs, single track and two main aid stations. Runners should carry water and be aware of exposed terrain and rattlesnakes.

Experience a flat and fast trail race through the scenic Quarry Lakes Regional Recreation Area in Fremont. Choose from a USATF certified half marathon, 10K, or 5K while enjoying views along the Alameda Creek Trail.

Navigate the redwood forests and meadows of Santa Cruz in this 2 or 4 hour map based adventure scramble. Explore the wilds in teams of up to five while hunting for 20 unique checkpoints.

Celebrate Thanksgiving at Hellyer County Park with a trail race along Coyote Creek. Choose from a USATF certified half marathon, 10K, or 5K while competing for a chance to win a turkey.

Quad Dipsea is a 28.4 miles trail event in Mill Valley, California, with about 9,000 feet of elevation gain. The route is an out and back to Stinson Beach repeated twice and includes aid stations at Cardiac Hill, Stinson Beach, and Old Mill..

A family friendly Thanksgiving weekend run at Quarry Lakes Regional Park with a half marathon, 10K, 5K and a free short kids race. Costumes and food donations for the Alameda County Community Food Bank are encouraged.