WIS 129 begins at a modified
T Intersection with US 61/WIS 35/WIS 81 in the
Town of South Lancaster, southeast of the city of Lancaster. (US 61/WIS 35/WIS 81 continues northeast into the city of Lancaster before WIS 35/WIS 81 diverges to head west, with WIS 35 heading toward
Bloomington and WIS 81 heading toward
Cassville. US 61/WIS 35/WIS 81 heads south, with WIS 81 quickly diverging to head southeast toward
Platteville and US 61/WIS 35 continuing south toward
Tennyson and
Dickeyville and then on to
Dubuque,
Iowa.) For its entire route WIS is
two-lane road located in rural
agricultural area. From it southern terminus, WIS 129 heads briefly northeast before curving to head north for the remainder of its route. About from the beginning of the highway, WIS 129 crosses Lincoln Road, which connects with Lancaster, and approximately later it reaches County Trunk Highway A (CTH‑A). Between Lincoln Road and CTH‑A, WIS 129 runs along the eastern
border of the city of Lancaster. (CTH‑A heads easterly to
Union,
Wisconsin Highway 80, and
Rewey, before ending at
U.S. Route 151. CTH‑A heads west through Lancaster as Elm Street to pass by the Grant County Fairgrounds and
Lancaster High School, before connecting with US 61 [Madison Avenue]. Beyond Lancaster, CTH‑A, continues westerly toward
Bloomington and
Bagley.) ==Major intersections==