Trail Running calendar near Clayton 2026-2027

A 22.5K event in Clayton, California on March 21, 2026, organized by Nomadic Adventure Club; registration closes March 20 and donations support the club’s free community initiatives.

A charity trail run on March 22, 2026, at Lake Lagunitas near Fairfax, CA. The 10 km course includes technical terrain and ~400 feet of elevation change, with proceeds beyond event costs donated to Evidence Action's Safe Water Now program.

A half marathon on March 22, 2026 in La Honda, California, the Horseshoe Lake course runs through Skyline Ridge Open Space Preserve with ocean and bay views. The trail mix and 2230' ascent support The Hatuey Project with entry fees matched..

Join Western Pacific 2026 at Quarry Lakes in Fremont for scenic half marathon, 10K and 5K routes along the Western Pacific and Alameda Creek trails. Mostly flat trails welcome runners, walkers and remote runners.

Trail races along single track by Folsom Lake on March 28, 2026, with 5K, 10K, 8 Mile and half marathon options. Courses feature dirt and rock surfaces, rolling hills, marked navigation and aid stations, and a commemorative medal for finish..

Trail races in the Marin Headlands near Mill Valley offering marathon, half marathon and 10K routes on single track and fire roads with views of the Golden Gate Bridge, San Francisco Bay and the Pacific Ocean. The field is limited to 400 pa..

Trail runs on Mount Diablo on April 4, 2026 offering 50K, half marathon, 10K and 5K distances with a portion of fees supporting Save Mount Diablo. The half marathon is included in the Brazen Ultra Half Series.

Trail events on April 4, 2026 from Folsom to Auburn include a 50 mile endurance run plus 25 and 10 mile options, with on-course aid, professional timing, finish medals, goody bags, and post race food and beverages.

The Romancing the Island Half Marathon will take place in Belvedere Tiburon on Saturday 11 April 2026. You can run between 10 and 21 kilometers.

Springtime trail races at Lake Sonoma include a Western States qualifying 100K, a 50K with a bridge crossing, and a women only Trail Sisters half, all centered at the Lake Sonoma Visitor Center with aid stations and camping options.

Challenge yourself on scenic Lake Chabot trails April 11, 2026 in Castro Valley with distances from 8K to 50K plus a free kids dash. Looped, well marked courses offer big climbs, frequent aid stations and finisher medals for all.

A multi-distance trail event in Pilot Hill, California on April 11, 2026, organized by Troy’s California Trail Runs, with courses on stony dirt paths across hilly terrain and lake views, offering distances from 5K to 50K.

A four-distance trail event in Calistoga that follows single track and fire road into the Mount St. Helena area. Routes include technical sections, long aid stretches, drop bag service at Highway 29, and finisher medals and shirts.

Run scenic singletrack by Folsom Lake at Outlands Endurance Race in Pilot Hill CA April 18 2026 with 25K, 50K and 50M out and back courses. Includes a hat, wood awards, a post race meal and Sierra Ultra Trifecta credit for 50K and 50M.

Trail races in April 2026 at Del Valle Regional Park offering Half Marathon, 10K and 5K distances with electronic chip timing. Finisher medals and t shirts are provided and walkers and hikers are welcome.

Horseshoe Lake Trail Run features 5 mile to 50K options plus a free kids dash on scenic Skyline Ridge with Pacific views. Marked trails, stocked aid stations, and finisher medals make it a rewarding day for trail runners.

A community fundraiser at Spring Lake Regional Park on April 18, 2026 featuring a half marathon, 10K and 5K. The low-waste event donates a portion of proceeds to Trione-Annadel State Park and includes a medal, shirt and post-race snacks.

Join the No Foolin' Foot Race in San Carlos on April 18, 2026 with 1K kids, 5K, 10K and a new 15K route across Big Canyon, Eaton and Pulgas Ridge. Festival vibes, tech shirts, pro timing and proceeds help local trails.

Trail races through Huddart County Park and Purisima Creek Redwoods on April 18, 2026, offering 10K, half, 35K and 50K courses with chip timing and marked aid stations. The event is limited to 450 runners and is a cupless format.

Trail race on Mt Tamalpais with a Half Marathon and 10K on coastal ridge single-track and road, limited to 300 participants, with aid stations, course markings, and participant t-shirts.