WIS 31 begins at the
Illinois state line where it connects to
Illinois Route 131 (IL 131), following Green Bay Road to its junction through
Pleasant Prairie. The highway briefly passes through the northwestern part of Kenosha.
WIS 50 and
WIS 158 cross WIS 31 in Kenosha. WIS 31 passes along the west side of
University of Wisconsin–Parkside south of the
Racine County line. In the Racine area, WIS 31 crosses
WIS 11,
WIS 20 and
WIS 38, turning onto Ole Davidson Road in
Caledonia. Green Bay Road, named after the historic route connecting
Chicago with
Milwaukee and
Green Bay, has been upgraded to four-lane divided highway for the entire length. Ole Davidson Road has been upgraded to a divided highway from the split with North Green Bay Road to Four Mile Road. ==Major intersections==