Underdown Trail Races

AUG
15
2026
Run intimate trail races on backcountry singletrack and scenic lakes near Merrill Wisconsin with 60k, marathon and half options. Proceeds support trail building, finishers get a commemorative mug and the day wraps with live music, food and beer.
Sat 15 Aug 2026
60 kilometers Marathon Half Marathon

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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.

60 km
60k
Marathon
Marathon
Half Marathon
Half Marathon