State Trunk Highway 178 (often called Highway 178, STH-178 or WIS 178) is a 23.3-mile (37.5 km) state highway in Chippewa County, Wisconsin, United States, that runs north–south roughly along the Chippewa River from Chippewa Falls to Cornell.

From Lake Hallie to Cornell, WIS 178 entirely follows the west bank of the river.

After intersecting CTH-S at the city limit, WIS 178 downgrades into a two-lane undivided roadway.

[5] In 2006 it was rerouted east of the city along Seymour Cray Sr. Boulevard to WIS 29.

[1] The entire route is in Chippewa County.