Underdown Trail Races
Merrill, United States • 15 Aug 2026
Underdown Trail Races
Scheduled for August 15, 2026 in Merrill, Wisconsin, the Underdown Trail Races combine trail running and mountain biking on the Underdown trail system. The event has been held since 1989 and uses backcountry singletrack trails shaped by glacial activity.
The event program includes these distances:
- Trail run: 60k, Marathon, Half marathon
- Mountain bike: 111 mile, 37 mile, 16 mile
The running and biking courses are primarily singletrack with multiple climbs, pass isolated lakes, and include dozens of boardwalks. The course is described as well-marked and stocked with aid stations; drop bag transport is provided. Field sizes are limited to preserve a more intimate trail experience.
Organizers note that much of the course goes through remote areas and that cell phone service may be spotty. The event materials describe the races as a physical and mental test and advise that participants consider their ability and experience in backcountry trail conditions. Finishers receive a custom commemorative Underdown mug and divisional awards. Additional event features listed include race photo downloads and an after-race gathering with live music, food, and beer. Proceeds from the event are used to build and maintain trails at the Underdown. Visit the organization's website for the most recent information.