Lean Horse Ultra Marathon, live.

A rail trail hundred through the Black Hills

The Lean Horse Ultra Marathon returns to Custer, South Dakota on 30 and 31 July 2027, on the George S. Mickelson Trail in the Black Hills.

Lean Horse was first run in 2005 and is held in late July every year. The course follows the George S. Mickelson Trail, an old railroad bed with a crushed limestone surface, so the climbs are long and gentle rather than steep. The organiser describes it as one of the best non technical courses in the United States.

The 100 mile race and the 100 mile relay, for teams of up to five runners, start at noon on Friday 30 July at the Custer YMCA. The course is an out and back to the turnaround at the DMTM Exchange, with a start at 5,316 feet, a high point of 6,262 feet and 7,162 feet of total climb. The 50 mile race starts at 5:00 am on Saturday 31 July from the Custer Track, and the 30 and 20 mile races start there at 8:00 am. The 30 mile course goes to Hill City and back, the 20 mile course to Oreville and back.

All races share a finish line cutoff of 8:00 pm on Saturday. There is also a 30 mile Black Hills CrossFit Edition for singles and teams of three or six. The organiser publishes GPX files for every course.

The average late July daytime high in Custer is 79 degrees with a low of 53, according to the race. The gentle grades and runnable surface suit people looking for a non technical hundred, and the 50, 30 and 20 mile races give shorter options on the same trail.

On Livebib you can follow a participant who chooses to share their own live position from the phone they carry. This is not the organiser's timing, and official results come from the Lean Horse Ultra Marathon.