The Hardrock Hundred Mile Endurance Run is an ultramarathon of 100.5 miles.
Here are the stats:
The race is held on a loop course, including 4WD roads, dirt trails, and cross-country terrain in Southern Colorado's San Juan Mountain range. The run begins and ends in Silverton, Colorado and travels through Telluride, Ouray and the ghost town of Sherman, and crossing 13 major mountain passes in the 12,000 to 13,000 foot (elevation) range. Completion of the event is marked by kissing the Hardrock, a picture of a ram's head painted on a large stone.
This is a graduate level endurance run. Mountaineering, wilderness survival, and wilderness navigation skills are key. The cut off time for finishing the race is 48 hours. Current course records are held by Killian Jornet (22:41) in 2014 and Diana Finkel (27:18) in 2009.
The Hardrock 100 is the centerpiece of the Rocky Mountain Slam, the completion of which requires a finish at the Hardrock race, and three of four other races in the Rocky Mountains (Leadville 100, Bear 100 Mile Endurance Run, Bighorn 100, and the Wasatch Front 100 Mile Endurance Run).