Trail Running calendar near Castro Valley 2026-2027

A multi-distance trail event on March 22, 2025 at Calero County Park in San Jose offering runs from a kids race to a 50K, single track and dirt-road courses, multiple aid stations, and per-distance time limits.

Multiple trail distances run through Redwood Regional Park on March 20, 2027 at Chabot Space & Science Center. Routes use East Ridge, West Ridge, Stream and Bridle trails and distances were measured with a Rolatape surveyor's wheel.

A backyard ultra at Dry Creek Parkway where runners complete repeated 4.16 mile loops each hour until one runner completes the most yards. The event is affiliated with the Backyard circuit and can lead to national and world championship opp..

A multi distance running event at Quarry Lakes Regional Recreation Area in Fremont, CA on March 27, 2027. The mostly flat course follows part of the historic Western Pacific Trail and includes a remote participation option.

A spring trail race at Pueblo Day Use Area in Santa Teresa County Park on April 5, 2025 offering 5K, 10K, 10 Mile and a half marathon across marked, hilly trails with aid stations and a four hour half marathon limit.

Multi-distance Spartan obstacle weekend in Stanislaus County, CA on April 3-4, 2027. Options range from a 5 km sprint to a 50 km ultra, plus a kids race, across trail terrain with signature obstacles.