Lean Horse Ultra

JUL-AUG
31-1
2026
Run the Lean Horse Ultra on the scenic Mickelson Trail in the Black Hills of South Dakota each August. Choose 100, 50, 30 or 20 mile distances or relay teams and enjoy a non technical rails to trails course with gentle climbs.
31-1 Jul-Aug 2026
100 miles 50 miles 30 miles 20 miles

Always double-check with the organizer's website! This page may contain affiliate links.

Event

The Lean Horse Ultra Marathon is held in August each year on the George S. Mickelson Trail in the Black Hills of South Dakota. The race was first run in 2005 and is hosted by the town of Custer. It includes multiple distance options and relay formats.

  • 100 Mile
  • 100 Mile Relay (up to 5 runners)
  • 50 Mile
  • 30 Mile
  • 20 Mile
  • 30 Mile Black Hills CrossFit Edition (Singles, team of 3, team of 6)

Course and conditions

The trail surface is crushed limestone and follows an old railroad bed, which produces extended gentle climbs along the route. Average August daytime temperatures at the event are listed as a high of 79 degrees and a low of 53 degrees.

The event is noted as a sanctioned 100-mile race in the United States and is described as a non-technical, scenic rails-to-trails course. Visit the organization's website for the most recent information.

100 mi
100 Mile
100 mi
100 Mile Relay
50 mi
50 Mile
30 mi
30 Mile Black Hills Crossfit Edition
30 mi
30 Mile
20 mi
20 Mile

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