A deceptively demanding 100-mile loop through San Diego's backcountry mountains and the PCT
San Diego 100-Mile Endurance Run takes place on May 01, 2026 in Lake Cuyamaca, CA.
San Diego 100-Mile Endurance Run is 100 miles with 12,600 ft of elevation gain.
No — San Diego 100-Mile Endurance Run uses open registration; no lottery is required.
Yes, crew is allowed at San Diego 100-Mile Endurance Run. Sign in to Trailrace to see crew access for each aid station.
Yes, pacers are allowed at San Diego 100-Mile Endurance Run.
Yes, San Diego 100-Mile Endurance Run allows drop bags.
San Diego 100-Mile Endurance Run has 14 aid stations along the course.
The overall cutoff for San Diego 100-Mile Endurance Run is 32h. Per-aid-station cutoffs are available to signed-in Trailrace members.
A 100-mile loop through the east county mountains of San Diego, traversing five distinct areas: Lake Cuyamaca, Rancho Cuyamaca and Anza Borrego State Parks, Noble Canyon, Mt Laguna Recreational Area, and the Pacific Crest Trail. The course runs 85–90% on technical singletrack at elevations between 3,000 and 6,000 feet, with roughly 13,000 feet of climbing and equivalent descent. Known in the ultrarunning community for being harder than its stats suggest, combining relentless technical footing, exposed PCT ridgelines, and significant temperature swings between hot dry afternoons and near-freezing nights. A Western States 100 qualifier and one of Southern California's longest-running 100-milers.
Suitable for first-timers
Lake Cuyamaca, CA, United StatesMay 01, 2026
Must complete a 50 Mile race or longer within the qualification window
Qualifying window: January 01, 2024 – April 01, 2026
Must have completed a 50-mile race in 13 hours or less, or a 100K or 100-mile within that race's cutoff, between January 1, 2024 and April 1, 2026.
All entrants must complete 6 hours of trail maintenance or volunteer service at an ultra or community event between June 1, 2025 and April 24, 2026. In lieu of hours, a $105 donation to the TrailFit Program is accepted. This requirement is strictly enforced — runners who do not comply will not be allowed to participate.
| Location | Mile | Elevation |
|---|---|---|
Cuyamaca Lake Start | 0.0 | 0 ft |
Trout Pond Aid Station | 12.7 | 0 ft |
Cuyamaca Peak Aid Station | 19.7 | 0 ft |
Green Valley Aid Station | 29.4 | 0 ft |
Blue Ribbon Aid Station | 35.6 | 0 ft |
Sweetwater Aid Station | 41.4 | 0 ft |
Pine Creek Road Aid Station | 49.5 | 0 ft |
Hammer's Hideaway Aid Station | 51.8 | 0 ft |
Penny Pines Aid Station | 59.2 | 0 ft |
Meadows Aid Station | 64.3 | 0 ft |
Red Tail Roost Aid Station | 70.6 | 0 ft |
Per's Cabin Aid Station | 75.6 | 0 ft |
Penny Pines Aid Station | 80.7 | 0 ft |
Pioneer Mail Aid Station | 84.6 | 0 ft |
Sunrise Aid Station | 91.6 | 0 ft |
Cuyamaca Lake Finish | 100.6 | 0 ft |
Sign in to see cutoffs, crew access, drop bags, and services for every aid station.
Camping available at Lake Cuyamaca Recreation Area near the start/finish. Additional options at Paso Picacho and Green Valley State Parks, plus RV hookups, cabins, and lodging in Julian and Mt Laguna Lodge.
The San Diego 100 runs in early May at elevations between 3,000 and 6,000 feet in the coastal mountain range east of San Diego. Expect significant daily temperature swings: afternoons can reach the low-to-mid 80s°F under intense sun with low humidity, while nighttime temperatures drop into the low 40s°F with possible near-freezing wind chill on exposed PCT ridgelines. Strong winds are possible at any point. The combination of afternoon heat, low humidity, and relentless technical terrain makes hydration and thermal gear management critical.
No required gear specified
No recommended gear specified
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