The Underdown Trail Races are grassroots trail runs in Northern Wisconsin. It’s conveniently located only 6 miles off of Highway 51 and offers runners a wilderness experience on challenging trails. We look forward to seeing you this summer.

The 50 mile run starts out on the Ice Age Trail


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 on challenging terrain that goes through some remote areas.
  • Cell phone service will be spotty at best.
  • You should consider your ability and fitness carefully before signing up. You should be comfortable being along and have experience taking care of yourself in the woods.
  • It is meant to be a physical and mental test that allows you to test your trail running mettle.
  • If you have not trail run before, we recommend signing up one of our shorter races first.
  • Bears are in the area. None were seen during the 2017 race, but they are present. You should be comfortable and have experience in the woods in this type of event before signing up.
  • Finish it and you just might burst with pride and happiness!

50 Mile Registration (Limited to 50 runners)


– $70 (Through 12/31/17)
– $85 (1/1/18 – 6/30/18)
– $100 (7/1/18 – 8/25/18)
(Plus UltraSignUp.com Fee). No day of race entry

*Please note that there is a $10 daily camping fee.

Each finisher of every distance will receive a finisher award. Awards will be given for the following:

  • 1st/2nd/3rd – (Age 39 & Under) Male and Female
  • 1st/2nd/3rd – (Age 40 & Over) Male and Female

Refunds, Transfers & Switches:

Entry fees are not refundable under any circumstance, however may be partially credited to another one of our events. Please contact us about transfers.

Waiting List:
We DO NOT keep a waiting list for those that did not get in prior to the race selling out.



We strive to provide you with a fun and challenging event that gives you a valuable experience. As part of that experience, you will get the following with your entry:

  • Well-marked, backcountry challenging singletrack course
  • Each registered racer receives the following:
    • Free custom, reusable Underdown Trail Race tote bag
    • Free custom, commemorative Underdown Trail Race pint glass
  • Custom top 3 awards
  • Finisher awards
  • Stocked aid stations
  • Complimentary coffee and hot chocolate before, during, and after the run for runners and guests.
  • Food and snacks pre and post run
  • After race party – grilled food, beer, and other goodies
  • Limited edition Underdown Trail Race apparel will be available for purchase


Friday, August 24th

4:00-9:00pm: Packet Pickup/Check In at Race Headquarters at the Underdown Rec Area

Saturday, August 25th

5:00am: Race Start [Please note that you need to have to coordinate your own ride to the start 18 miles away]

3-4pm: Estimate of First Finishers.

Awards will get going after we have a good amount of award winners in. We don’t want to make you hang around all day.

10:00pm: Race Finish Cut Off Time

Times are subject to change


50 Mile Course:

1st Section of Course from Start to Race HQ (Mile 0-17)

Course from HQ to Finish (Mile 17-50)(Please note that this section is not completely final)


  • Elevation Gain: You can expect about 50-100 feet per mile. This terrain is very much glacial, up and down, and not easy. Expect a wilderness type experience on tough terrain.
  • Surface/Surroundings: Mostly forest singletrack with a few gravel road crossings. The ground there is a result of glacial deposits. You can expect rocks, roots, dry to loamy dirt and everything in between. You’re traversing all the ups and downs that the glaciers left behind. In sections you’ll be on hillsides and then you’ll drop down into areas that have marshes near the trail. You’ll see lakes, ponds, and A LOT of trees.
  • Aid Stations: You can expect stocked aid stations at several locations. The course crosses gravel roads several times, so you have plenty of crewing access as well. Some aid stations are manned by volunteers and some will be self serve. Food and Drink – Aid stations will have the following beverage and food choices available (but not limited to): Water, Tailwind Nutrition, Soft Drinks, Fruit, Peanut Butter Sandwiches, Chips, Potatoes & Salt, Cookies, Candy. *If you have special dietary requirements, please make sure to make use of your drop bags. The following is a map of the aid station locations. Aid stations #2 and #4 are larger, manned aid stations. The other aid stations will be more basic with water, Tailwind Nutrition, and other food items and may or may not have someone tending them – they may be self serve.

  • Pacers & Crew: Pacers are not allowed. Any runner found running with a pacer who is not a registered runner (“a bandit”) will be disqualified.  Your crew members may offer support anywhere on course.
  • Info For Crews, Spectators and Family (runners please share this with your crews): It is critical that every runner’s crew or a spectator drives slowly and stays away from other runners near the aid stations.  Vehicles near or at an aid stations can ruin the day for everyone.
  • Headphones: We do not recommend the use of headphones. However, we won’t tell you can’t wear them. Full awareness of one’s surroundings, and the ability to communicate with other participants, race volunteers, and trail users not associated with the event are critical to everyone’s safety.
  • Littering: Please don’t litter. If you are caught in the act of littering on course, you will be asked to leave and not invited back. If you see some trash someone else has dropped, please pick it up.  There will be garbage bags at the aid stations.
  • If You DNF: If you have to quit the race, please call or text 608-385-2706 with your name and number or alert the nearest aid station and they will alert that number. You are responsible to get yourself off course and back to home base. If you leave the course and fail to notify race officials, you are not welcome back to our races.


 [Course is subject to changes ]



These following pictures give you a good idea of what the trails and area of the Underdown Recreation Area are like. We’ll get more pictures of the trails and course this spring and summer and post them here.

Check out these videos from the Underdown Recreation Area



If you have any questions about the results, send an email to info@gritevents.com

Each finisher will receive a finisher award. Awards will be given for the following:

  • 1st/2nd/3rd – Age 39 & Under Male and Female
  • 1st/2nd/3rd – Age 40 & Over Male and Female


It’s important that you use common sense, follow the rules, and be nice to ensure everyone’s enjoyment, safety, and overall experience. If you break the rules or do any other shenanigans, we have the final decision in dq’ing you. If you see someone being “one of those people,” you can find someone involved with the race and we will handle. Thanks for being nice.

  • NO LITTERING. This applies to on course, in the parking lot, and everywhere. Please pick up any garbage you see, no matter how small it is.
  • Runners must race under their own name/registration. Runners who bandit the race by running under someone else’s name and registration will not only be disqualified, but you will also never be allowed to race any of our races ever again. We’re serious.
  • If you drop out of the race, you must notify a race official and/or timing.
  • Racers cannot stash support including nutrition, equipment, or any other gear or items on course prior to the race. We are providing an aid station and 50k and 50 milers will get to have a 2 gallon drop bag.
  • Headphones are allowed but we discourage the use of them. We won’t tell you not to wear them, but your full awareness of your surroundings and your ability to communicate with everyone is important for everyone’s safety.
  • Strollers, dogs, bikes, and other non-running items are not allowed.
  • Racers cannot receive outside support on course during the race, except at designated aid stations.
  • Racers must let faster runners pass when it’s safe for them to do so.
  • Pacers are not allowed.
  • Racers must stay on course. Cutting the course is not permitted and really lame.
  • Be nice.

Cancellation/Weather Policy

***Registration and transaction fees are nonrefundable, including in the event of extreme weather or cancellation. Registration is not transferable to another person or another event for any reason, including injury. Competing under another person’s name will result in disqualification. In the event of poor conditions, we are held to park rules and will try our best to provide an alternate course and gathering if possible. If it’s not possible, the event will be cancelled.***



For emergencies: DIAL 911


Ministry Sacred Heart Hospital  
401 West Mohawk Drive
Tomahawk, WI 54487
(715) 453-7700


Ministry Good Samaritan Health Center
601 S Center Ave,
Merrill, WI 54452
(715) 536-5511


Aspirus Wausau Hospital
333 Pine Ridge Blvd,
Wausau, WI 54401
(715) 847-2121


Hotels: Merrill and Tomahawk have several options to choose from and are the closest. Wausau offers several as well.

Camping: Camping is available on site and it is first come, first serve basis. This is primitive camping. There is a pit toilet, no electric hookups, and no running water. It’s quiet and convenient and a good option. Please note that there is a $10 daily camping fee.


The following are some links to give you information about the Underdown Recreation Area:

Lincoln County Website – http://www.co.lincoln.wi.us/services/u/?service=19fe1b63b3bb

Thunderdown in the Underdown Blog – http://thunderdown12.blogspot.com/ [This is kept up by Chris Schotz, who is responsible for the trails existing the way they do now. It’s an awesome resource and we all owe Chris a huge virtual round of applause]


Any lost items found after the race will be donated. Please check before you leave the venue.


If you need to stop the race for any reason, you need to notify timing. If you quit and leave the course without notifying the race, we will not let you attend again. We take the safety of everyone very seriously and don’t want to leave anyone out on course in bad shape.