Rim Rock 50 Mile Trail Challenge

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..

The Reservoir Dogs Trail Run takes place at the San Pablo Reservoir / Briones Reservoir area (East Bay Municipal Utility District), Orinda / El Sobrante, CA, on October 4, 2025. Distances offered are: 35K : 23.4 miles, 2,800 ft elevation gain Half Marathon : 13.9 miles, 1,450 ft elevation gain 10K..

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..

The event is a time-based trail run held at Skyline Wilderness Park in Napa, California. Runners compete to cover as much distance as possible within a chosen time limit. The event capacity is 400 participants across all options. 12 Hour 6 Hour 3 Hour The course is a loop of 4.16 miles with appr..

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..

Diablo Summit Stomp is a Brazen Racing trail race in Walnut Creek, California, starting at Castle Rock Park and venturing into Mount Diablo State Park toward the summit. Runners can choose from 30K, half marathon, 10K, or 5K, all on dirt trails with hills and potential mud or creek crossings dependi..