It runs in north–south in northwest Wisconsin from near Elmwood to Forest.

The highway begins at an intersection with WIS 72 and runs north from it, following the Eau Galle River until its intersection with County Trunk Highway B (CTH-B), from which it continues north.

It then continues north before curving eastward to meet WIS 170 in Glenwood City.

[5][6] In 1947, WIS 79 moved off from Glenwood and instead served Connorsville.

[7][8] By 1994, WIS 128 moved eastward onto the existing bypass of Spring Valley, superseding CTH-T. As a result, CTH-B was established to follow along part of the former alignment.