Rim Rock 50 Mile Trail Challenge

Berkeley Trail Adventure is an Inside Trail Racing event set in Berkeley, CA, spanning Tilden Regional Park and Wildcat Canyon. Distances offered are 50K (31 miles), 35K (21.6 miles), half marathon (13 miles), and 10K. The course blends technical dirt trails and non-technical fire roads, with about..

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..

Reservoir Dogs Trail Run, held in Orinda, CA on October 4, 2025, features three distances—10K, Half Marathon, and 35K—starting and finishing at the San Pablo Reservoir Recreation Area in EBMUD land. This race was the first to completely circumnavigate Briones Reservoir on permit trails, offering tre..

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 Napa Lapa Trail Adventure, held at Skyline Wilderness Park in Napa, California, is Inside Trail Racing’s first time-based ultrarun. Runners compete for a set amount of time rather than a fixed distance, choosing to cover as much terrain as possible within 3, 6, or 12 hours. Each loop is about 4...

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..