sentences:  The route was first shown on official maps in 1924; the original route ran along Sheridan Road from the Wisconsin border to Waukegan, then turned west along Washington Street, south along Green Bay Road (now part of IL 131), east along Rockland Road (now part of IL 176) before running south along Waukegan Road (now mostly part of IL 43).In 1925, Route 42 was realigned to include all of Sheridan Road in Illinois; the route continued south to the Indiana border at Hammond, and the old route became Illinois Route 42A.In 1929, the southern terminus of Route 42 was changed to the south end of Sheridan Road, making the route coextensive with the Illinois portion of Sheridan Road.