Trail Running calendar near Fairfield 2026-2027

Trail races at Mammoth Bar OHV Area in Auburn on September 6, 2026. Single-track and double-track courses include steep climbs, descents and views of the American River Canyon across Half Marathon and 10K options.

Diablo Trail Run on September 6, 2026 in Clayton CA offers distances from a 4 mile Mitchell Canyon course to a 50K, plus a free kids 50 yard dash for age six and younger. Courses use dirt roads and single track with aid stations every 3 to..

Trail races on September 12, 2026 in Tilden Regional Park and Wildcat Canyon offering 50K, 35K, half marathon and 10K courses with marked trails, aid stations every five to seven miles, and a cupless format requiring reusable cups or bottle..

Explore scenic trails along Folsom Lake at the Gold Rush Growler Trail Runs. Choose between a 10-mile or 5K course starting at Granite Beach. Finish with a custom beer glass, a local IPA, and a hearty post-race meal.

Rocky Ridge is a trail race in the Las Trampas Wilderness on September 19, 2026. Choose from half marathon, 10K, or 5K distances on hilly courses with scenic views. It is part of the Brazen Ultra Half Series.

A multi distance trail event at Lake Chabot Regional Park in Castro Valley featuring a 100k, a 50 mile, and a marathon. All races are UTMB Index events and the 50 mile is part of the Pacific USATF Grand Prix.

Explore the shaded redwood groves and challenging, flowy singletrack of Sanborn County Park. This trail event on September 27, 2026, offers 10k, half marathon, and 50k distances through the Santa Cruz Mountains.

Trail running event in Auburn, California on October 3, 2026 offering half marathon, 12K and 5K distances. The half course follows the Western States Trail and crosses No Hands Bridge, with start and finish at Overlook Park.

Trail races in Auburn, California in October 2026 run along the American River Canyon with 50K, half marathon, and 5 mile options. Postrace items include a commemorative cider glass, a Ponderosa Cider pour for those 21 plus, and age group a..

Run the 39th Ruth Anderson Memorial Endurance Run on October 10, 2026 in San Francisco. Choose 100 km, 50 miles, or 50 km on a scenic paved loop around Lake Merced with chip timing and certified 50K and 50 mile courses.

Granite Head Trails and Ales offers two scenic fall trail runs at Granite Beach, California. Runners will encounter dirt trails, granite boulders, and a sandy beach along Folsom Lake. All finishers receive a tech shirt, medal, and post-race..

A trail event in Cool, California on October 17, 2026 offering 5k, 10k and a trail half marathon. Proceeds support Black Oak Mines Unified School District youth and a Camp Taylor scholarship, and the event includes family options.

A multi-distance trail running festival in Healdsburg during harvest, combining the Lake Sonoma 50 with a new 100 mile race, a trail marathon, and relay options on nearby trails.

Trail races from a kids run to a half marathon take place inside Marshall Gold Discovery State Historic Park in Coloma, CA. Courses mix singletrack and paved trails with technical climbs, scenic views, aid stations, and finishers' medals.

A trail running event on Mount Diablo in Walnut Creek. Runners can choose from a 30K, half marathon, 10K, or 5K distance on scenic trails. Walkers are welcome, and conditions may include mud and creek crossings.

A Halloween-themed running event at Hellyer County Park offering distances from a kid's 50 yd dash to a certified marathon, with costume prizes, aid stations every 2-4 miles, and cupless hydration policy.

A trail fundraiser in Joaquin Miller Park offering a 5 km trail race and a 1 mile fun run/walk to support Oakland Tech PTSA and the school cross country program; donations are tax-deductible.

Two trail endurance races start from Beal's Point near Folsom Lake, offering a **100 mile** route and a **50K** course with marked trails, aid stations, B tag timing and finisher awards.

Mermaid Trail Run at Huddart Park in Woodside on November 7, 2026 features multiple trail distances, a timed 6 Hour challenge and a youth dash. The course is hilly, parking has a cash fee and a pancake breakfast follows the race.

A multi-distance trail event around Lake Chabot in Castro Valley on November 7, 2026, offering 8K to 50K options plus a free kids' dash, marked trails, regular aid stations, and a cupless policy.