This coverage contains highway related information included in the IDOT Illinois Highway Information System (IHIS) -- Illinois Roadway Information System (IRIS). Information is collected for all public highways as defined in Illinois Compiled Statutes (605 ILCS 5/2-202). A separate coverage is provided for each of the 102 counties, each of the 9 IDOT districts, and the state of Illinois.

Complete metadata along with IRIS Manual are located here:

V:\Documentation\External_Data_Documentation\IDOT

• hwy_metadata_2023.txt

• ILHwyInfoSystem_IRISManual_201407.pdf