Lean Horse Ultra
Always double-check with the organizer's website! This page may contain affiliate links.
Lean Horse Ultra Marathon
The Lean Horse Ultra Marathon is an annual ultrarunning event in the Black Hills of South Dakota. The 2026 edition is scheduled for July 31 to August 1, 2026, and is hosted in Custer, South Dakota.
Distances offered include:
- 100 mile race
- 50 mile race
- 30 mile race
- 20 mile race
- 30 mile Black Hills CrossFit Edition - Singles, 3 person, and 6 person relays
The course follows the George S. Mickelson Trail and uses a crushed limestone surface. Because the trail follows an old railroad bed, the elevation profile shows extended gentle climbs rather than steep, technical sections.
The event was first run in 2005 and is listed as the 33rd sanctioned 100 mile race in the United States. Event information describes the trail as non-technical and scenic. Average August daytime temperatures for the area are about a high of 79 degrees and a low of 53 degrees.
The description focuses on course type, distances, location, terrain, and typical August temperatures to help potential participants understand the setting and format of the event. Visit the organization's website for the most recent information.
