CWOCC oversees the development and maintenance of 6 trail systems in the area. Nine Mile, The Big Eau Pleine, The Underdown and Prairie Dells. The remaining two, Sylan Hill and Ringle Trail System are now in development. In conjunction with The Wausau Marathon County Parks, Recreation and Forestry Department, Lincoln County and Merrill City Parks System, we are excited to help bring these trails to our local riders as well as the visiting riders to the area.

Nine Mile County Forest

With over 12 miles of single track, Nine Mile County Forest is great place for all levels of mountain bikers to ride. A variety of terrain gives the rider plenty of play-in-the-dirt fun. From the flowey Yin to Yang to the technically advance expert loop, Nine Mile has it all.

Just 4 miles west of HWY 51 which makes it easy to get to. There are pit toilets and water back by the County garage.

MTB Project  | Directions

Big Eau Pleine County Park

Big Eau Pleine Park is a sizeable park containing 1,450 acres of second-growth mixed hardwoods forming a two-mile peninsula thrust deep into the waters of the Big Eau Pleine Reservoir.  The majority of the park was gifted to Marathon County in 1937 by Consolidated Water Power Company.  The park operates two seperate campgrounds with a total of 106 sites.  8 miles of technical single track with 12 miles of developed trails allow hiking and horseback riding.  Visitors can also fish and there are several fishing points near the entrance of the park and adjacent to the three boat landings in the park.

Directions | MTB Project


Underdown is a legendary network of rugged and challenging single track that features 4 lakes, 5 bermed boardwalks and 64 hills through the vast Lincoln County Forest.  A blend of old-school and machine-built trail overlaps a segment of the Ice Age Trail and a separate multi-use trail utilized mainly by horses. Camping is available for $15 at the Copper Lake Road trailhead or in the backcountry, especially at the Dog Lake primitive shelter and Underdown Lake.  Riding the Underdown and  Prairie Dells trails together can stretch the adventure beyond 30 miles. A snowshoe trail gives fat bikers a dreamy ride over frozen lakes and bogs.

MTB Project

Praire Dells

The Prairie Dells loop is a moderate difficulty route built by machine through 1000 acres belonging to the City of Merrill.  Parking is available at the Merrill Memorial Forest trailhead near the junction of Heineman Road and County Highway R.  Riders will enjoy wildlife from the Manthei Marsh boardwalk or views on the Prairie Dells canyon.  A connector trail across Heineman Road allows riders to flow over ice marginal ridges to the extensive Underdown trail system.  This loop is groomed for swoopy fat biking in winter.

MTB Project

Sylvan Hill Mountain Bike Park

A one-of-a-kind mountain bike park in Wisconsin, Sylvan Hill Mountain Bike Park is the newest trail system in the Wausau area.  After years for collaboration between CWOCC, the City of Wausau and Marathon County Park, Recreation and Forestry Dept., Rock Solid Trail Contracting was hired to construct this all encompassing bike park.

The system is comprised of one main loop, the easiest of the trails. Off that loop, are three jump-line/flow trails that progressively get more difficult all the way to double black diamond.

At the trailhead is a pump track and skills area to help refine your abilities and prepare you for the big lines.