List of U.S. Highways in Illinois

United States Numbered Highway System in Illinois
Standard Illinois U.S. Highway markers
System information
Maintained by IDOT, ISTHA, and CDOT
Formed	November 11, 1926 (1926-11-11)[1]
Highway names
Interstates	Interstate X (I-X)
US Highways	U.S. Route X (US X)
State	Illinois Route X (IL X)
System links
Illinois State Highway System Interstate US State Tollways Scenic

This is a list of U.S. Highways in Illinois, all of which are owned and maintained by the U.S. state of Illinois. The Illinois Department of Transportation (IDOT) is responsible for maintaining the U.S Highways in Illinois. The system in Illinois consists of 20 primary highways.