Illinois 131 is a fairly short north-south route running parallel to Lake Michigan's west shore. Upon crossing northward across the Wisconsin border, it becomes Wisconsin Route 31 (hence the number 131). It runs completely within Lake County.
Intersections from north to south:
IL131 begins at the Wisconsin border
IL173 near Zion
IL132 at Waukegan
IL120 at Park City, near Waukegan
IL137 at North Chicago
IL131 ends at its southern terminus, which is the eastern endpoint of IL176 at Lake Bluff.
It passes through these towns: Winthrop Harbor, Zion, Waukegan, Park City, North Chicago, and Lake Bluff.
