For its entire route WIS is two-lane road located in rural agricultural area.

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.

After about another 0.5 miles (0.80 km) WIS 129 curves to the northwest immediately before reaching it northern terminus at US 61.

US 61 heads southwesterly into the city of Lancaster and northerly toward Fennimore and La Crosse.