The Hardrock Hundred Mile Endurance Run is an ultramarathon of 102.5 miles in length, plus 33,197 feet of climb and 33,197 feet of descent for a total elevation change of 66,394 feet, at an average elevation of over 11,000 feet. The run is held on a loop course on 4WD roads, dirt trails, and cross country in Southern Colorado's San Juan Range.