For die-hard physical fitness fans, join the fun in late August, when the annual Lean Horse Marathon (www.leanhorsehundred.com , registration 100-mile $170, 50-mile $95, 50K $95) takes place. The start of the race is at the Chamber of Commerce office at the Mueller Center (801 S. Sixth St., 605/745-4140 or 800/325-6991, www.hotsprings-sd.com ). There are three separate races—a 100-mile race, a 50-mile race, and a 50K race.
The bulk of the race is run on the Mickelson Trail, with the 50-mile race traveling the distance between Hot Springs  and Hill City . The 100-milers run to Hill City and back. The 50-mile and 100-mile races start at 6 a.m., with the close of the 50-mile race set at 6 p.m. the same day. The 100-mile race closes at noon the day after the race begins. That’s an amazing 12 hours and 30 hours of running, respectively.
The 50K race is a point-to-point race that starts at the Carroll Creek trailhead, just south of Custer , on the Mickelson Trail and finishes at the Mueller Center in Hot Springs. Transportation to the starting point of the race is available if necessary. The start time of the 50K race varies from year to year. Check the race website for updates.