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South Dakota · Custer
Lean Horse
Jul 31, 2026
Founded in 2005 as the 33rd sanctioned 100-miler in the United States, Lean Horse runs out-and-back on the George S. Mickelson Trail — a converted railroad bed in the Black Hills of South Dakota — on crushed limestone with average 2% grades and 7,162 feet of total climbing. Runners leave the Custer YMCA at noon Friday and have until 8:00 PM Saturday to reach the DMTM Exchange turnaround and return. Pacers join at mile 50. The men's course record is 15:14 (Paul Hopwood, 2012); women's is 16:55 (Jenny Capel, 2008).
The numbers
Race statistics
- Distance
- 100 mi
- Vertical gain
- 5,000 ft
- Course
- Out & back
- Unique miles
- 51 mi
- Entry fee
- $300
- Lottery
- No
- Sub-24 hr
- 30%
- Avg finishers
- 55
50 ft / mi
of finishers
per year
The course
Course line from published GPX · source · approximate — always follow official markings
◈ From the runners