Underdown Trail Races
Merrill, United States • 15 Aug 2026
Underdown Trail Races
The Underdown Trail Races take place at the Underdown Trail system near Merrill, Wisconsin in August 2026. The event is organized by IRONBULL, a nonprofit, and is located about 6 miles off Highway 51. The running event offers limited fields for an intimate trail experience and directs proceeds to building and maintaining trails at the Underdown.
Distances
- 60k
- Marathon
- Half marathon
Course and logistics
The course is primarily backcountry singletrack that climbs hills and passes by isolated lakes. There are dozens of boardwalks on the race route. The event notes that the terrain is challenging and that parts of the course go through remote areas where cell phone service will be spotty. Aid stations are stocked and drop bag transport is provided. Finishers receive a custom commemorative Underdown mug. Divisional awards and digital race photos are offered. An after-race party includes live music, food, and beer. A separate mountain bike event, Thunderdown in the Underdown, is also listed with multiple distances and is part of the Wisconsin Endurance Mountain Biking Series. Visit the organization's website for the most recent information.