The Ouray 100 Mile Endurance Run is held in July in the San Juan Mountains of Colorado, covering approximately 161 km with 12,290 m of total elevation gain. The high-altitude course begins and ends in the historic mining town of Ouray and traverses rugged alpine terrain, reaching elevations above 4,200 m. The race carries 10 ITRA endurance points and has a 52-hour cutoff.