Lean Horse Ultra Marathon Custer, South Dakota, United States
Event description
The Lean Horse Ultra Marathon is run in late July on the George S. Mickelson Trail, a crushed limestone rail trail through the Black Hills of South Dakota, based in Custer. It has run since 2005 with out-and-back 100 mile, 50 mile, 30 mile and 20 mile races, plus a 100 mile relay and a 30 mile Black Hills CrossFit Edition. The 100 mile starts at the Custer YMCA on Friday, and the shorter races start at the Custer Track on Saturday.
Course maps
Foot race
|
31 Jul 2027
50.2 mi
Distance
Elevation gain
5,866 ft
Elevation high
5,381 ft
Elevation avg
Course last updated 15 Nov 2026
Stats summary
| Race distance | Distance | Ele gain | Ele loss | Ele avg | Paved | Gravel | Dirt | Narrow |
|---|---|---|---|---|---|---|---|---|
| 20 Mile | 19.8 mi | 1,483 ft | 1,483 ft | 5,587 ft | 2% | 0% | 98% | 99% |
| 30 Mile | 29.7 mi | 2,024 ft | 2,024 ft | 5,443 ft | 1% | 0% | 98% | 99% |
| 50 Mile | 50.2 mi | 3,107 ft | 3,107 ft | 5,381 ft | 6% | 1% | 93% | 98% |
| 100 Mile | 100.0 mi | 7,175 ft | 7,136 ft | 5,387 ft | 2% | 1% | 97% | 97% |
Foot race
30-31 Jul 2027
No registration link
Event history
Race data contributors
Nick Knipe