Underdown Trail Races
Save the date: August 16, 2025
MERRILL, WI
Underdown Trail run:
60k, Marathon, half marathon
Thunderdown in the underdown Mountain bike:
111 mile, 37 mile, and 13 mile
what are the Underdown trail races?
Dozens of boardwalks on the race course!
Still rowdy since 1989, the Underdown Trail Races are grassroots trail runs and mountain bike races in Northern Wisconsin. It’s conveniently located only 6 miles off of Highway 51 and offers racers a wilderness experience on challenging trails formed from glaciers that swept the area thousands of years ago. The course is primarily singletrack climbing hills (up to 75!) that pass by isolated lakes with dozens of boardwalks. If you need a course description, listen to the event’s theme song here!
***PLEASE NOTE THE FOLLOWING WARNINGS***
Bikers take part in the WEMS.
We want to be straightforward and make sure that you’re not getting into something you don’t expect.
This is a challenging trail run/bike on challenging terrain that goes through some remote areas.
Cell phone service will be spotty.
You should consider your ability and fitness carefully before signing up. You should be comfortable being alone and have experience in the woods in this type of event before signing up. Bears are in the area.
It is meant to be a physical and mental test.
If you’re new to the sport, we recommend signing up one of our shorter races first.
Finish it and you just might burst with pride and happiness!
RACER GUIDE
Read race rules, print the race schedule, and important crewing information.
The 2024 race guide is linked below for reference until the 2025 race guide is released.
WHAT DO YOU GET?
Custom pint glass in use
We strive to provide you with a fun and challenging event that gives you a valuable experience. Each distance is limited to provide a intimate trail experience for each participant. As part of that experience, you will get the following with your entry:
Proceeds from this event go back to build and maintain trails
Backcountry challenging singletrack trails
Well-marked, backcountry challenging singletrack course
Custom, commemorative Underdown pint glass for finishers
Finisher awards
Stocked aid stations and drop bag transport
After race party with a live music from The Northwoods Skitchers, food, beer, and other goodies
Race photo digital downloads
Proceeds go back into building & maintaining trails at the Underdown
WEMS Series
The Thunderdown in the Underdown mountain bike race continues to be part of the Wisconsin Endurance Mountain Biking Series (WEMS) races. More info on WEMS races here.
Race team profiles
Race Director Chris Schotz
EVENT SPONSORS
City of Merrill - for visitor information, call the Merrill Area Chamber of Commerce at 715-536-9474 or visit www.merrillchamber.org
