Underdown Trail Races

Prepare for an unforgettable journey into the heart of Northern Wisconsin's wilderness at the Underdown Trail Races on August 15, 2026, in Merrill, WI. Offering challenging distances of 60K, 26.2M (Marathon), and 13.1M (Half Marathon), this grassroots event delivers a true backcountry experience on glacially formed singletrack trails. Runners will navigate a course renowned for its "rollercoaster" feel, boasting up to 75 hills, dozens of scenic boardwalks, and views of isolated lakes, with some sections traversing the iconic Ice Age Trail. Expect a physical and mental test on terrain that is primarily forest singletrack with substantial elevation gain—around 100 feet per mile—in remote areas where cell service can be spotty.

What sets the Underdown Trail Races apart is not just the demanding course, but its vibrant atmosphere and commitment to the trails. Originating as a mountain bike race in 1989 and combining with the trail run in 2021, the event is praised for its camaraderie and a high overall experience rating from participants. You'll find well-stocked aid stations with drop bag transport, ensuring runners are supported throughout their adventure. Upon conquering the trails, finishers are celebrated with a custom commemorative mug and an lively after-race party featuring live music, delicious food, and local brews.

Beyond the race day excitement, your participation directly contributes to the preservation and expansion of this remarkable trail system, as proceeds are reinvested into building and maintaining the Underdown trails. With typical race day conditions seeing highs around 78F and lows around 56F, and a modest 16% chance of precipitation, it's an ideal setting to challenge yourself amidst the "fresh country air, beautiful forest, and wonderful wildlife" that runners consistently rave about.