San Diego 100
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San Diego 100 : Lake Cuyamaca, CA
The San Diego 100 is a 100 mile mountain loop held at Lake Cuyamaca Recreational Area. The course is approximately 90% single-track and traverses four recreational areas in San Diego County, including sections of the Pacific Crest Trail, Noble Canyon, Cuyamaca and Anza Borrego State Parks, and Mt Laguna recreation areas. The route includes roughly 15,600 feet of climbing and an equivalent amount of descent, and is run with a 32 hour time limit.
Two entry options are offered: a crewed division and a Solo division. Solo entrants may be met only at the start and finish, must rely on drop bags and aid stations for support, and receive a special award for finishing. Crews and pacers are allowed in the crewed division.
Registration opens January 1, 2027 and remains open until 200 entrants have registered or until April 15, 2027; an ordered waitlist will be maintained if the race fills. As a prerequisite to enter, applicants must have completed a qualifying performance between January 1, 2025 and April 1, 2027: a 50 mile race under 13 hours, or a 100K or 100 mile within that event's time limits. Entries must also complete six hours of trail maintenance or volunteer service between May 1, 2026 and April 15, 2027, or donate $100 to support volunteers and local trail work. This requirement is strictly enforced.
Runners aged 60 and over may start one hour earlier than other runners; aid stations open at the usual times so early starters should be prepared to self-support until the Cuyamaca Peak aid station. Organizers will award up to two free entries to applicants who demonstrate community service; nominations of two to three paragraphs are due by December 28, 2026. A 10 percent discount is available for active military and first responders by arranging a discount code with the organizers. Visit the organization's website for the most recent information.
