Trail Running calendar near Clayton 2025-2026

Pacifica Summit Run, staged at San Pedro Valley State Park in Pacifica, California, features 10K and half-marathon trail races hosted by Urban Coyote Racing. Runners enjoy postcard views of the Pacific Ocean coastline and plenty of switchbacks as they ascend the summit on the upper San Francisco Pen..

JP's Backyard Ultra/Hike is a grassroots ultramarathon and hike held at Skyline Wilderness Park in Napa, California. In its third year, the event features a 3.3-mile loop with 550+ feet of climbing through rocky and shaded trails. Runners and hikers may do 1 to 10 loops, starting together on the hou..

Dick Collins Firetrails is the 42nd annual trail event presented by Scena Performance at Lake Chabot Regional Park (17936 Lake Chabot Rd). The event comprises multiple trail races on East Bay regional trails, including sections on Dinosaur Ridge, the Garin-Chabot Trail, Skyline Gate, Reinhardt Redw..

Spartan Trail San Jose Challenge takes place at Sanborn County Park in the eastern Santa Cruz Mountains near Saratoga, California, with the race site at West Valley College Parking Lot 5. The event offers three trail distances: 50K, 21K, and 10K. Runners tackle well‑groomed yet steep and difficult t..

The Trailblazer Race in Mountain View, CA, is an annual family-friendly event featuring 10K and 5K runs, plus a 3-mile walk along the scenic Stevens Creek Trail and Shoreline Park. The courses are fast, flat, and stroller-friendly, offering beautiful views of wildlife, salt ponds, and surrounding mo..

The Women's Headlands Half Marathon is a scenic 13.2-mile trail race held annually in the Marin Headlands near Mill Valley, California. Celebrating its third year in 2025, the event features a challenging course with nearly 2,000 feet of elevation gain, showcasing stunning singletrack trails, sweepi..

Star City San Bruno Mountain Half Marathon & 5K, organized by the Excelsior Running Club, takes place in Brisbane, CA, on the San Bruno Mountain trails. The course is 93% on trail with about 2,400 feet of elevation gain, including a single-track downhill and sweeping views of the Pacific, Bay, and S..

The Women's Headlands Half Marathon is a trail running event held in the scenic Marin Headlands near Mill Valley, California. This race features a brand-new half marathon course that highlights the area's stunning singletrack trails, challenging climbs, and exhilarating descents, offering runners a..

The Reservoir Dogs Trail Run takes place on Saturday, October 4, 2025, at San Pablo and Briones Reservoirs (EBMUD) in Orinda, CA. The event has a capacity of 300 runners across all distances. Parking is available at the San Pablo Reservoir Boat Launch with a $7 fee; carpooling is encouraged. Dogs a..

Run by the Sea is an annual running event held at Wilder Ranch State Park in Santa Cruz, California. Scheduled for October 5, 2025, the race offers three distances: a 4K run/walk, a 12K run, and a half marathon. The courses primarily follow flat, packed dirt trails along the scenic coastal bluffs of..

Mile Madness Endurance Run takes place at Sunset Whitney Recreation Area in Rocklin, California. The race uses a 1.05-mile loop (85% dirt, 15% paved) with about 62 feet of elevation per lap and a central Start/Finish hub. Runners choose from 6-, 12-, 24-, 48-, or 72-hour events, plus a 100-mile chal..

The Mt. Umunhum Trail Conquest-Fall is a trail running event held at Almaden Quicksilver County Park in San Jose, California. The race offers multiple distances including a 5K, 7 Mile, Half Marathon, 30K, Trail Marathon, and 50K.The longer courses venture into the scenic Sierra Azul Open Space Prese..

Go Wild Marin offers a trail and wilderness navigation challenge in Corte Madera, California, with 2-hour and 4-hour options. Teams of 1 to 5 use a custom map to locate up to 24 checkpoints scattered along trails and wild areas of the Tiburon Peninsula. The event emphasizes exploration and navigatio..

Ruth Anderson Memorial Endurance Run is an ultramarathon held in San Francisco, California, circling Lake Merced. Runners complete a multi-lap course on a 4.475-mile paved bike path, with aid stations at the start/finish and each loop. The event features distances associated with a 50M designation,..

The Napa Lapa Trail Adventure is a time-based trail run held on October 11, 2025, at Skyline Wilderness Park, 2201 Imola Ave, Napa, CA 94559. Entrants run for a pre-determined amount of time and complete as many loops as possible. Event options are: 12 Hour 6 Hour 3 Hour Each loop is approximatel..

Granite Head Trails & Ales is a trail running event on Saturday, October 11, 2025, in Granite Bay, California. Both race courses start and finish at Granite Beach. The event is presented by Altra and the local contact is Fleet Feet Sacramento. The event supports fundraising efforts; one listed..

The John Lawson Tamalpa Challenge is a three-race cross-country event held at Miwok Meadows in China Camp State Park, San Rafael, California. Each 4.2-mile course follows rolling single-track trails with about a quarter-mile on asphalt, starting near the Miwok Meadows gate and finishing in the Miwok..

Vampire Run - Unite for Bleeding Disorders is held in Roseville, CA, at Vernon Street Town Square in Downtown Roseville. It features a first-ever 5K on the Roseville trails, offered as a timed run with adult 5K and child 5K (under 14) and adult and child 1-mile options. The event fosters a festive,..

The 16th Annual Willow Hills XC Open is organized by the Buffalo Chips Running Club and is part of the Pacific Association USATF Cross Country Grand Prix. The event is held in Folsom, California, on Saturday, October 18, 2025. A bonus of $75 is awarded to any runner who breaks an age group course r..

The California Fall Classic at Lake Sonoma offers two ultramarathon distances: 100K and 55K, run at Lake Sonoma near Healdsburg, California. The weekend features on-site camping, live music, and local food, wine, and beer, with proceeds supporting the Children of Vineyard Workers Scholarship Fund. R..