Trail Running calendar near Thornton 2026-2027

A point to point half marathon to the summit area of Mt. Umunhum on March 8, 2025, covering about 13.35 miles with 4,767 feet of ascent, marked mainly by pink ribbons and supported by aid stations with toilets.

A three-day trail running event in Marinwood, California on March 19 to 21, 2027 offering 100K point to point and 50K and 28K single-loop courses that summit many of Marin County’s high points with broad bay area views.

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 dog-friendly trail event at Granite Beach, Folsom Lake, offering 10K, 5K and a one-mile Mighty Mile. Finishers receive medals and bandanas, awards are given by dog-size divisions, and volunteers can earn a $50 voucher.

An hourly backyard ultra on Dry Creek Parkway near Sacramento where runners repeat a 4.16 mile loop until only one completes the most yards. Each loop must be finished within the hour and the last runner to complete a loop wins.

Western Pacific 2027 at Quarry Lakes Regional Recreation Area in Fremont offers Half Marathon, 10K and 5K races on a mostly flat course along the historic Western Pacific Trail. A remote runner option is also available.

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.

A weekend obstacle course event at Stanislaus County Parks offering multiple races from a kids run to a 50 km ultra, with technical trail sections and signature obstacles across grasslands and hills.

A trail running event at Mount Diablo on April 3, 2027 offering 50K, half marathon, 10K and 5K options; registration includes a remote-runner option and BBQ ticket. Part of the entry fees support Save Mount Diablo's land preservation.

A women's only 10K in Auburn on April 17, 2027 that follows scenic trail loops with aid stations and age-group awards; the overall winner and four additional finishers will be selected to receive all-expenses-paid trips to a women's running..

A trail event at Skyline Ridge Open Space Preserve offering distances from a 50 yard kids dash to a 50K race. Routes run largely on the Bay Area Ridge Trail with ocean and Santa Cruz Mountains views.

A multi-distance trail event in Auburn, California, following sections of the Western States Trail with river crossings and historic trail features. The 100K awards Golden Tickets to the top three men and women for Western States entry.

A trail event at Lake Chabot Regional Park offering distances from a 50‑yard kids dash to a 50K ultramarathon. The looped course circles the Lake Chabot reservoir and surrounding hills with measured distances.

No Foolin' Foot Race in San Carlos on April 24, 2027 offers 15K, 10K, 5K and a 1K kids trail course across Big Canyon, Eaton and Pulgas Ridge, with proceeds supporting local open space trail maintenance.

The The Wine Half Marathon will take place in Yountville on Saturday 8 May 2027. You can run 21 kilometers.

Run for Amma is a charity trail event on May 16, 2026 at Skyline Ridge Open Space Preserve near Los Gatos. Multiple distances from 10K to 50K are offered and all registration proceeds support UCSF cancer research.