San Diego 100

Julian, United States • 8 May 2026

San Diego 100 is a challenging 100-mile ultramarathon in Lake Cuyamaca, California, starting and finishing at the Lake Cuyamaca Recreation Area south parking near Julian. The loop course is about 90% single-track mountain trails, crossing four San Diego east county recreation areas and segments of the Pacific Crest Trail, Noble Canyon, Cuyamaca, and Anza-Borrego parks, with Mt. Laguna included.

Runners face hot, dry, technical terrain with roughly 15,400 feet of climbing and the same amount of descent, capped by a 32-hour limit. It’s a Western States 100 qualifier, celebrated for superb volunteers and support. Notable features include a 60+ early start and a Solo Division with unique awards. Visit the organization's website for the most recent information.

Race information

100 mi
15400 m+
100 Miles
Visit the organization's website for the most recent information.
Trail runs nearby

The Cuyamaca 100K is an ultramarathon held in Cuyamaca Rancho State Park near Julian, California, about an hour east of San Diego. The race features a challenging 100-kilometer course composed of three distinct loops starting and ending at Camp Cuyamaca. The first loop covers 31.5 miles on the park'..

The Mount Laguna Trail Marathon, held in Mount Laguna, California, is a well-organized Southern California trail race featuring a challenging single-loop course of technical single-track trails. The marathon covers rolling terrain with a total elevation gain of 3,358 feet. The first half of the cour..

Anza Borrego Cuyamaca 50 Mile Run is a point-to-point ultramarathon covering 50 miles from the Sunrise Trailhead near Julian, California, to Stagecoach Trails RV Resort & Campground. The course climbs to Stonewall Peak, winds through wooded trails near a lake, then descends into Oriflamme Canyon and..

The Dixon Lake 10/10 Trail Race is the 5th annual event held at Daley Ranch in Escondido, California. The event date is December 13, 2025. The venue address is El Caballo Park, 3450 E. Valley Parkway, Escondido, CA 92027. The 10-mile course reaches the top of Stanley Peak and includes a 360-degree..

Del Dios Trail Race, billed as The Race of the Gods, unfolds at Lake Hodges in Escondido, California. The event offers four distances: 5K (3.1 miles), 10K (6.1 miles), Half Marathon (13 miles), and a 50K (31 miles). Courses traverse dirt service roads and single-track trails, with elevation gains ra..

San Diego 50 & Trail Runs is a multi-distance trail running festival staged at the San Pasqual Valley Staging Area in Escondido, California. The lineup includes a 50-mile ultramarathon, a Trail Marathon (plus a 2-person relay), a Trail Heavy Half, Summit Chase 10M (with a youth version), plus Valley..