The Hardrock Hundred Mile Endurance Run is an ultramarathon of 100.5 miles in length, with 33,050 feet of climb and 33,050 feet of descent, at an average elevation of over 11,000 feet. The race is held on a loop course on 4WD roads, dirt trails, and cross country in Southern Colorado's San Juan Range, USA. Starting in 1992, the run has been held every year except 1995 (too much snow) and 2002 (nearby forest fires).