August 15 – 16, 2025

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RACE OVERVIEW

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.

*30-Mile Black Hills CrossFit Edition Singles and relay teams of 3 or 6.

Course Overview

  • Surface: Crushed Limestone
  • Course: Mickelson Trail
  • Elevation Profile: Extended gentle climbs. This is due to the fact the course is on an old railroad bed
  • Hosting Town: Custer, South Dakota
  • Average August Daytime Temperature: High of 79 degrees.  Low of 53 degrees.

Fun Facts

  • 33rd sanctioned 100-mile race in the United States
  • Known as one of the best non technical courses in the United States
  • One of the most scenic rails to trails courses in the country

Learn about Custer, South Dakota

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RACE OVERVIEW

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.

*30-Mile Black Hills CrossFit Edition Singles and relay teams of 3 or 6.

Course Overview

  • Surface: Crushed Limestone
  • Course: Mickelson Trail
  • Elevation Profile: Extended gentle climbs. This is due to the fact the course is on an old railroad bed.
  • Hosting town: Custer, South Dakota
  • Average August Daytime Temperature: High of 79 degrees.  Low of 53 degrees.

Fun Facts

  • 33rd sanctioned 100-mile race in the United States
  • Known as one of the best non technical courses in the United States
  • One of the most scenic rails to trails courses in the country

Event Distances

Event Media

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