Illinois State Highway System

State Highway System
Interstate 57 marker
U.S. Route 45 marker
Illinois Route 1 marker
Chicago Skyway marker
Highway markers for Interstate 57, U.S. Route 45, Illinois Route 1 and the Chicago Skyway
Overall map of system: freeways in light blue, tollways in green, other highways in yellow
System information
Maintained by IDOT, ISTHA, and SCC
FormedNovember 5, 1918 (1918-11-05)[1]
Highway names
InterstatesInterstate X (I-X)
US HighwaysU.S. Route X (US X)
StateIllinois Route X (IL X)
System links

The organized State Highway System of the U.S. state of Illinois comprises all of the state routes in the state.

  1. ^ Carlson, Miriam C. (April 2002). "Out of the Mud: Illinois' Good Roads Movement". Illinois History. 55 (3). Illinois Historic Preservation Agency: 47–9. ISSN 0019-2058. Archived from the original on 2013-06-09. Retrieved 2014-04-25 – via Illinois Periodicals Online.