High Lonesome 100
Mount Princeton, United States • 17-18 Jul 2026
High Lonesome 100
Established in 2017, the High Lonesome 100 is a mountain endurance race held in the Sawatch Range of the Colorado Rocky Mountains. The event features a 100 mile loop course that starts and ends at the base of Mount Princeton. The route transects the southern end of the range, utilizing the San Isabel and Gunnison National Forests.
The course reaches a high point of 13,100 feet and has a total elevation gain of approximately 23,300 feet. Much of the race takes place at high altitude, with an average elevation of 10,426 feet and 15 percent of the course situated above the tree line. The terrain consists of:
- 66% single track
- 27% mining roads
- 4% paved roads
- 3% gravel roads
Participants travel through diverse landscapes, including five alpine passes, remote basins, soaring ridges, and two ghost towns, St Elmo and Hancock. The route includes 27 miles of the National Scenic Continental Divide Trail and 35 miles of the Colorado Trail. The race has a total time limit of 37 hours.
Registration involves a lottery process, and runners must meet specific qualification requirements and gear standards. The event also mandates a trail work requirement for entrants. Support is provided by aid stations captained by experienced ultra-marathon runners, and the race allows for crewing and pacing under specific regulations. Visit the organization's website for the most recent information.