San Diego 100
Lake Cuyamaca, United States • 1 May 2026
Event overview
The San Diego 100 is a 100 mile loop ultramarathon with start and finish at the south parking area of Lake Cuyamaca Recreation Area, located near Julian, California on Highway 79. The course is about 90% single-track trail and includes sections of the Pacific Crest Trail, Noble Canyon, Cuyamaca and Anza-Borrego State Parks, and Mount Laguna recreational areas. The course has approximately 15,400 feet of climbing and about the same amount of descent and has a 32 hour time limit. The event is a qualifier for Western States 100.
Entry, rules and services
Applicants must have completed a 50 mile race in under 13 hours between January 1, 2023 and May 1, 2025, or have completed an applicable 100K or 100 mile within the time limits of that event in the same time frame. Runners must complete six hours of trail maintenance or six hours of volunteer service between June 1, 2024 and May 15, 2025, or donate $100 in lieu of trailwork; failure to meet this requirement will bar participation. Organizers allow a one-hour earlier start option for runners over 60, with the note that aid stations will open at their usual times so early starters should be prepared to self-support until the Cuyamaca Peak aid station. The race includes a Solo Division with restrictions on crew and pacers, and finishing Solo runners receive special awards. Organizers also offer two Scotty Mills scholarship entries and a 10% discount for active military and first responders. Entry fees were increased to cover a required private ambulance. Visit the organization's website for the most recent information.