Hardrock 100 | Hardrock Hundred Mile Endurance Run The Official Hardrock Hundred Mile Endurance Run, or Hardrock 100, is an 100-mile ultramarathon race with 66,000 feet of elevation change 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 the San Juan Mountain Range of Southern Colorado. Hardrock100.com~Site InfoWhoisTrace RouteRBL Check Similar Sites: hardrockhundred.com