August 20-21

The Lean Horse Ultra Marathon is run in August every year in the Black Hills of South Dakota. It was first run in 2005. It features a 100-mile race, a 50-mile race, a 30-mile race, and a 20-mile race. The course is held on the George S. Mickelson Trail.

Lean Horse 100 – “Lean Horse 100 Foot Race” (leanhorseultra.com)