The route is partially a divided highway with a few freeway bypass sections for roughly 50 miles (80 km).

WIS 26 provides direct access from Janesville to Oshkosh via Fort Atkinson, Watertown, and Waupun.

WIS 26 begins in downtown Janesville, Rock County at U.S. Highway 51 (US 51, North Parker Drive), and follows East Centerway Street, to turn northeast on Milton Ave.[2] WIS 26 crosses US 14 and Interstate 39/Interstate 90 (I-39/I-90) on the northeast side of the city.

[3] The highway turns northeast at the county line and approaches Fort Atkinson, but turns northwestward prior to entering the city, and bypasses it to the west with four exits to serve Fort Atkinson.

About four miles (6.4 km) north of I-94, WIS 26 bypasses Watertown to the west as the highway crosses into Dodge County.

The highway then angles northeastward over the remaining seven miles (11 km) before entering Winnebago County.

[6] Four more miles (6.4 km) into the county the highway terminates at its interchange with I-41/US 41 on the far southwest side of Oshkosh, about two miles (3.2 km) south of the Wittman Regional Airport, site of EAA AirVenture Oshkosh.