Trail Running calendar near Fairfield 2026-2027

Island loop races at Angel Island State Park with sweeping bay views; a 10K single loop and a Half Marathon that does two loops, limited to 400 participants and requiring ferry transport.

A steep 4.75 mile up and down run, hike, or walk on San Anselmo's Bald Hill that finishes downtown with live music and a t shirt. The third annual event benefits local nonprofits and includes town endorsement.

A PA/USATF cross country race of 3.4 miles at Spring Lake Regional Park in Santa Rosa on August 30, 2026. The 33rd annual Empire Open features rugged dirt trails, three races including a masters division, and a $1,500 prize purse for USATF..

Trail races at Mammoth Bar OHV Area in Auburn State Recreation Area on September 6, 2026. Options include a 13.1 mile half marathon and a 6.2 mile 10K, each with notable elevation gain and staffed aid stations.

Multi-distance trail event at Mount Diablo offering races from 4 miles to a 50K plus a free kids dash. Mountainous routes have significant elevation gain, marked courses, staffed aid stations, and a cupless hydration policy.

A 6.45 miles trail race in Annadel State Park organized by the Empire Runners Club, held in early September with staggered age and gender starts, limited to 100 runners and awards for the top 13 finishers.

Experience the trails of China Camp State Park with a selection of distances including a 5K 10K and Half Marathon. Participants enjoy a post race festival with beer steins custom medals and local snacks.

Trail running at Tilden Regional Park in Berkeley with 50K, 35K, half marathon, and 10K options; aid stations appear every 5 to 7 miles and the event is cupless so participants carry their own bottle or reusable cup.

Trail races at Stevens Creek Reservoir in Cupertino on September 12, 2026 include a half marathon, an 11K, and a charity 2.5 mile Lollipop Loop. Courses use shaded single track and ridge views with aid stations and a post race BBQ.

A trail running event at Calero County Park offering distances from a kids run to a 50K across single-track and dirt roads, with named aid stations, drop bag support, bib color assignments, and time limits for longer races.

A looped endurance event in Auburn, California from September 18–21, 2026 offering timed runs from 6 to 72 hours, a 100 mile race, glow run, and relay options on a one mile loop with full aid support.

Trail runs at Granite Beach on Folsom Lake with new 10 mile and 5K courses, aid stations, age group awards, a finisher beer glass and a postrace meal.

Trail running event in Las Trampas Wilderness on September 19, 2026, offering a half marathon, 10K and 5K with hilly trail terrain and scenic vistas. Remote participation options and a parks campership fundraiser are included.

A trail 5K at San Pedro Valley Park on September 20, 2026, with a kids run and member picnic. The course features an uphill switchback first mile, scenic mid-mile views, and a flat fast final mile.

A multi-distance trail event at Lake Chabot Regional Park offering a Bay Ridge 100k, Firetrails 50 mile, and Golden Hills Marathon with UTMB Index status, published time limits, and finisher awards.

An ultramarathon and hike at Skyline Wilderness Park featuring a 3.3 mile loop with 550 plus feet of climbing and flexible 1 to 10 loop options. On-site awards, a raffle and a silent wine auction support the Pheo Para Alliance.

Trail running in shaded redwood forest at Sanborn County Park on September 27 2026, with 10K, half marathon and 50K options; steep singletrack, shuttle parking, chip timing and specific mandatory gear for the 50K.

Trail races along the Western States Trail near Auburn, California on September 27, 2026. Distances include a half marathon, 12K and 5K with electronic chip timing and finisher medals and t shirts.

Trailblazer Race in Mountain View on September 27, 2026 features 10K and 5K races, a 3 mile walk, and a kids 1 mile fun run, with awards, finish line timing for 5K and 10K, and proceeds supporting the Friends of Stevens Creek Trail.

Experience a trail half marathon on San Bruno Mountain featuring 2,400 feet of elevation gain and stunning views. Enjoy a scenic route with 93 percent trail coverage followed by a post race meal and finishers medal.