Trail Running calendar near Thornton 2026-2027

A trail event around San Pablo and Briones Reservoirs offering 5K, 10K, half marathon and 35K on single track and fire roads. Aid stations, race shirts, and a 300 runner capacity are part of the event.

A rugged fatass trail event near Foresthill, CA offering 25 mile and 50 mile options with extensive off trail sections, large climbs, limited to 50 entrants, free to enter.

Trail races in Nevada City on October 11 2026 include a new half marathon plus 10K and 5K options. Courses mix pavement gravel and single track with aid stations and historical points along the way.

Insomnia is a night trail race in the Sierra Nevada foothills offering 35K, 14K and 5K options. Courses are marked with reflective ribbons and headlamps are required; the 35K has a 5 hour 30 minute overall cutoff.

A trail running event in Cool, California on October 17, 2026 offering 5k, 10k and a half marathon. Proceeds benefit Black Oak Mines Unified School District youth programs and help fund a scholarship to Camp Taylor.

Trail races in Marshall Gold Discovery State Historic Park offer distances from a Kids Run to a half marathon on singletrack and paved sections, with marked courses, aid stations, a 4.5 hour time limit, and on site parking for a fee.

A trail running event at Mount Diablo in Walnut Creek on October 17, 2026 offering 30K, Half Marathon, 10K and 5K courses on hilly trails where mud and creek crossings are possible.

A 5k cross country race run in two loops around Willow Hill Reservoir next to Folsom High School, part of the Pacific Association USATF Cross Country Grand Prix, with a $75 bonus for breaking an age group record.

A themed charity run and community festival on October 18, 2026 in Downtown Roseville, CA, supporting the bleeding disorders community. The day includes a timed 5K, a one mile walk, festival food, carnival games, and a remembrance ceremony.

An endurance event at Beals Point in Granite Bay where runners complete an hourly 4.16 mile loop until one remains. A 12 hour Mini Last Person Standing uses the same format with a fixed time limit.

A repeating 4.16-mile trail loop event at Beals Point where runners start a new lap each hour until one remains; a Mini version ends after 12 hours. Aid is only at the start/finish and personal aid areas are encouraged.

The Rubicon is a remote on and off trail backcountry foot race near Oxbow Reservoir, CA. It offers three routes from about 15 to 43 miles with substantial elevation gain and multiple water crossings.

Experience the autumn scenery of Jenkinson Lake at the Trail Run at Sly Park. This event offers distances from a 5K to a 50K ultra on shaded pine forest trails with rolling hills and lakeside views.

Trail races near Pilot Hill, CA featuring a half marathon and a 10K on singletrack with creek crossings and views; the event is a fundraiser for the American River Conservancy and is limited to 175 participants.

Trail races of several distances take place October 24, 2026 at Bothe-Napa Valley State Park near Saint Helena. The single track courses feature hills, streams, orange ribbon markings, aid stations, and a 300 participant limit.

Trail races in Redwood Regional Park near Oakland offering 10K, half marathon and 35K with significant elevation and technical dirt trails. Aid stations provide food and electrolytes and the event is cupless so runners must carry their own..

A Halloween-themed running event at Hellyer County Park with 5K, 10K, half and full marathon distances, youth divisions, a free kids' dash, a costume contest, certified half and full courses, aid stations every 2-4 miles, and cupless hydrat..

Trail races in Almaden Quicksilver Park from 5K to 50K over hilly dirt roads and single-track, with two staffed aid stations, drop-bag service for longer distances, and a finisher medal for all participants.

Support student programs and the Oakland Tech Cross Country team at Joaquin Miller Park. Choose between a five kilometer trail race or a one mile fun run through the redwood trees.

Event Details The Rio Del Lago 100 Mile Endurance Run is a trail race held on Saturday, November 7, 2026, starting at Beal's Point in Folsom Lake State Recreation Area, within the Sierra Foothills of California. Course Information The 100-m..