| State: | WI |
| Type: | WI |
| Route: | 107 |
| Map Custom: | yes |
| Map Notes: | WIS 107 highlighted in red |
| Length Mi: | 56.23 |
| Length Ref: | [1] |
| Length Round: | 2 |
| Direction A: | South |
| Direction B: | North |
| Terminus A: | in Mosinee |
| Terminus B: | in Tomahawk |
| Counties: | Marathon, Lincoln |
| Previous Type: | WI |
| Previous Route: | 106 |
| Next Type: | WI |
| Next Route: | 108 |
State Trunk Highway 107 (often called Highway 107, STH-107 or WIS 107) is a state highway in the U.S. state of Wisconsin. It runs in a north–south direction in central Wisconsin from west of Mosinee to south of Tomahawk.
WIS 107 begins at its intersection with WIS 153, a little more than 5miles west of Mosinee. Most of WIS 107's routing travels through the remote areas of central Wisconsin, following the flowage of the Wisconsin River.
WIS 107 heads due north from WIS 153 into the village of Marathon City, where it becomes Main Street. Crossing the Big Rib River, it meets up with WIS 29 at the latter's exit 156.
WIS 107 continues north into the unincorporated community of Little Chicago. About two miles north of the Marathon/Lincoln County line, it intersects with Wisconsin Highway 64 and continues north, then east, with WIS 64 towards Merrill.
Entering Merrill, WIS 107 and WIS 64 run alongside the banks of the Wisconsin River, across from Council Grounds State Park. After briefly running through the city of Merrill's Sixth Ward along West Main Street, the two highways cross over the Wisconsin River—twice. The river is divided by a small island where West Main Street crosses into the uptown portion of the city of Merrill.
The two highways separate at the Y-intersection of Grand Avenue and Main Street; WIS 64 continues east over the Prairie River into downtown Merrill, while WIS 107 turns sharply to the northwest along Grand Avenue.
WIS 107 continues northwest, past the Merrill Area Recreation Complex and the main entrance to Council Grounds State Park, before turning north out of the city.
North of Merrill, WIS 107 runs along the eastern banks of the Wisconsin River as a rural two-lane highway all the way to its northern terminus with County Trunk Highway S (CTH-S) outside of Tomahawk. The terminus is somewhat unusual, as state highways in Wisconsin normally end at another state trunk highway. CTH-S, however, was the former route of US Highway 51 (US 51) as it entered Tomahawk. When the US 51 bypass freeway was finished east of the city, the former route of US 51 was turned back to county control, resulting in the unusual terminus.