An out-and-back on the smooth, crushed-limestone George S. Mickelson Trail through the Black Hills of South Dakota — the 33rd sanctioned 100-mile race in the country, and widely regarded as one of the best non-technical courses for a first 100-mile finish.
Quick facts
- Location: Custer YMCA, 644 Crook Street, Custer, SD (start/finish); turnaround near Deadwood
- Date: July 31, 2026, 12:00 PM Friday start
- Distance: 100 miles, out-and-back on the Mickelson Trail; finish cutoff 8:00 PM Saturday (32 hours)
- Website: leanhorseultra.com
- Contact: Via contact form at leanhorseultra.com
- Registration: Via UltraSignup, closes July 12 the year of the race. First run in 2005; the 33rd sanctioned 100-mile race in the US.
Course description
An out-and-back entirely on the George S. Mickelson Trail, a converted rail line running through the Black Hills between Custer and the Deadwood area. The crushed-limestone surface and old railroad grade mean extended, gentle climbs rather than any real steep terrain — one of the least technical 100-mile courses in the country. Along the way runners pass through several of the trail’s four historic tunnels (the longest over 1,100 feet) and cross more than 100 bridges and trestles, threading through granite outcrops and dense Ponderosa pine forest characteristic of the Black Hills.
Elevation change
Start elevation 5,316 feet, max elevation 6,262 feet, with 7,162 feet of total cumulative climb over the full out-and-back — gentle grades throughout thanks to the old rail bed, with no single steep or sustained climb.
Aid stations
Aid stations every 4–6 miles along the trail, including Mountain, Oreville, Hill City, Red Fern, Mystic, Rochford, and Nahant on the outbound leg toward the turnaround, all well-stocked and volunteer-staffed. Detailed aid station distances, cutoffs, and crew driving directions are published on the race website ahead of each race.
Special conditions & average temps
Late July/early August in the Black Hills typically brings a daytime high near 79°F and overnight low near 53°F — mild by 100-mile standards, though the region’s elevation and dry air mean sun exposure and temperature swings are still a factor over 32 hours on the trail.
Recent results — top 3, men & women
2025
- Men: 1. Matt Smith 16:41:00 · 2. Justin Alpaugh 18:07:52 · 3. Nathan Michael 19:43:56
- Women: 1. Jess Mullen 22:14:42 · 2. Lisa Albers 23:08:42 · 3. Kelly Tarricone 23:13:36
2024
- Men: 1. Daven Oskvig 18:05:00 · 2. Jon Rieckmann 18:21:11 · 3. Max Hofmann 19:45:49
- Women: 1. Jane Murawski 20:47:31 · 2. Piper Gray 22:14:26 · 3. Taleigh Adrian 22:19:08
2023
- Men: 1. Austin Baade 18:34:01 · 2. Dan Church 21:00:05 · 3. Johnathan Karol 21:11:24
- Women: 1. Sarah Graves 21:38:47 · 2. Candice McMackin 24:44:57 · 3. Renee Guthrie 25:34:34
Registration deadline & how to get in
Registration is handled through UltraSignup and closes July 12 of the race year. No qualifying race is required to enter. Lean Horse’s forgiving, non-technical surface and gentle grades have made it a popular choice for runners attempting their first 100-mile finish.
Traveling to this race? Find lodging near the venue via Hotels.com.