For the love of the dirt

For some people, the classic 5K run/walk just isn’t enough anymore.

Endurance events have rapidly grown in popularity over the past decade, attracting dedicated runners, bikers and hikers to beautiful natural surroundings and daring them to test their mettle against the elements and ultimately, against themselves.

While many events nationwide focus on drawing massive crowds and big-budget productions, the Underdown Trail Races offer something beautifully simple: a chance to disconnect from the daily grind and reconnect with nature and good friends. Kept intentionally intimate and proudly “rowdy” since 1989, this weekend’s wilderness event isn’t about who crosses the finish line first. It’s about a dedicated outdoor community coming together to celebrate their gratitude for the area’s pristine woods.

Proudly rooted in the handcrafted trails of Merrill’s Underdown Recreation Area — just six miles off Highway 51 — the Underdown Trail Races are less of a high-stakes competition and more of an annual family reunion. It’s a day where a deeply connected community of runners and riders head into the wilderness not for profit or podiums, but simply for the love of the trail.

“The purpose of this race is to really celebrate the area without becoming too commercialized of a race. It’s really again just a party for people to go explore the Underdown and to have a good day,” said Melissa Teeple, executive director of Ironbull, which helps organize the event.

Underdown is more than a race, it's a place where outdoor enthusiasts gather every year to celebrate one of Wisconsin's outstanding trail systems.

Photo courtesy of Ironbull

Taking place this Saturday, Aug. 15, the Underdown Trail Races offer a grueling test of endurance. The weekend features ultra-trail runs — ranging from a half-marathon up to a rigorous 60K — alongside the notoriously demanding “Thunderdown in the Underdown” mountain bike races, which span 16, 37 and a staggering 111 miles. But despite the punishing, glacier-carved terrain of boardwalks, bogs and 75 relentless hills, the atmosphere at base camp is decidedly laid-back.

“There’s people that have been racing this event for decades, all the way back into the ’80s and ’90s, that just want to get out there and have a good time,” Teeple said. “They’re going to come and talk to their friends afterwards, so having a space where they can come, hang out with people, that feels good is really important — and that’s just as important in other ways to newer people, too.”

That relaxed, connective vibe is entirely by design. The races are directed by Chris Schotz, who spends thousands of hours moving dirt and carving out trails in the remote backcountry of Merrill.

“Chris is such an asset to this community and this trail system,” Teeple said. “His entire life is building these trails so that people can have the most fun on them possible and showing off and accessing them in a way that is sustainable.”

The Underdown Trail Races are held Saturday, Aug. 15 at Underdown Recreation Area in Merrill.

Photo courtesy of Ironbull

Spearheaded by Schotz and supported by the city of Merrill with organizational help from Ironbull, the event is capped at roughly 200 participants. This limit protects both the delicate, water-heavy ecosystem and the intimate, homecoming culture of the race.

“What Chris and people that are involved with this trail system say is that this is the most amazing trail system that Central Wisconsin has and it’s just really overlooked,” Teeple said. “So you’ll see a lot of the stuff that you see on the more adventure-type trails ... rocky, sandy, rolling terrain, kind of like Ice Age Trail vibes but for bikes.”

There are no corporate profit margins here. As a purely grassroots endeavor, race proceeds are funneled directly back into the dirt — funding the machinery, materials and countless volunteer hours required to maintain this rugged singletrack system. For the athletes crossing the finish line to a live band, food and beer, their registration fee is a direct investment in the wilderness they love.

“The money that’s made goes back into the trails,” Teeple said. “There’s no profit for Ironbull or Chris or anyone else involved aside from putting on the race.”

Mud, dirt and grime are regular parts of the Underdown Trail Races, which take competitors through a water-dense ecosystem.

Photo courtesy of Ironbull

Future events

While the Underdown Trail Races operate as a fiercely independent heritage party in the woods, they are championed by Ironbull, a Wausau-based nonprofit dedicated to making outdoor recreation accessible for everyone. Ironbull has a full slate of events scheduled for the rest of 2026 to help Central Wisconsin residents find their next adventure.

The Rib Mountain Trail Races return on Saturday, Sept. 12. Dubbed the “steepest test in the Midwest,” this race sends runners up Rib Mountain’s rocky, root-heavy singletrack. New this year, the loop-based format ensures that runners of all distances — whether tackling a 10.5-mile single loop or a multi-loop ultra — start at roughly the same time, allowing beginners and seasoned veterans to share the trail.

A highlight for cyclists every year is the Red Granite Grinder, which is set for Saturday, Oct. 10. Starting and ending in Athens, this gravel ride features 20-, 50-, 100- and 150-mile routes across rolling farmland and Marathon County’s signature red granite roads. Designed to be highly accessible (the 20-mile route is just $25), the event finishes at the Athens Fall Fest and is capped off with a stargazing presentation by an astronomy professor.

Adventure doesn’t stop with the warm weather. Ironbull’s winter edition of the Rib Mountain Adventure Challenge on Saturday, Dec. 5, is a unique, map-and-compass orienteering challenge on bikes and on foot. Participants don’t even know the starting headquarters until the week of the race and only receive their maps an hour before launch, adding a thrilling layer of mystery for the 200-plus winter racers.

“It’s different in that you’re not following a set course, you just have to go find as many [checkpoints] the fastest way possible or the most streamlined way as possible on the course and then you finish all together,” Teeple explained. “It’s a mix of fat biking and trekking, and then our one in the spring also has canoeing in it.”

Despite the thrilling, adrenaline-oriented marketing of these events, Teeple made it clear that Ironbull works hard to develop a low-pressure, fun atmosphere at its events. Those who usually jog or cycle by themselves, only participate in 5Ks or are looking to start their fitness journey are encouraged to participate at Ironbull events and join the welcoming community of outdoor enthusiasts.

“All of us that are maybe craving a little bit more connection, there’s no better way to authentically just meet people that are easy to be around and that you want to be around,” Teeple said. “That’s what sport is to me and I think to many others: testing ourselves, finding people that we can enjoy it with, share a beer, share a non-alcoholic beverage and just enjoy life a little bit more in these increasingly hard times. So come out and have fun with us — there’s really not much to lose.”

For more information on upcoming events, visit ironbull.org.