San Diego 100
Lake Cuyamaca, United States • 1 May 2026
San Diego 100
The San Diego 100 is a 100 miles mountain loop event held at Lake Cuyamaca Recreation Area near Julian, California on May 1 and 2, 2026. The start and finish area is located at the south parking area of the recreation area. The course runs through multiple east county mountain recreation areas and state parks.
The route is approximately 90% single track and traverses sections of the Pacific Crest Trail, Noble Canyon, Cuyamaca and Anza Borrego State Parks, and Mt Laguna Recreational Areas. The course records roughly 15,400 feet of ascent and the same amount of descent. The event is run with a 32 hour overall time limit and serves as a qualifier for Western States 100.
Two entry formats are offered: crewed 100 mile runners and a Solo division. Solo entrants must rely on drop bags and aid stations and may be met only at the start and finish; Solo finishers receive a special award including a unique belt buckle. Solo entrants receive a $10 entry discount and switching from Solo to supported entry after registration requires a $10 fee.
Registration opens January 1, 2026 and is limited to 300 entrants on a first come, first serve basis, with a waitlist if the field fills. Applicants must provide a qualifying performance completed between January 1, 2024 and April 1, 2026. Entrants must also complete six hours of trail maintenance or volunteer service between June 1, 2025 and May 1, 2026 or donate $100 to Trailfit; this requirement is strictly enforced. A 10 percent discount is available for active military and first responders; contact the organizers for details. Visit the organization's website for the most recent information.