Federal Route 45 goes the longest distance of any Federal or State Highway in Illinois. It enters Illinois from Wisconsin in northeastern Illinois and crosses the Ohio River into Kentucky. It passes through the Chicago area, as well as Kankakee, Champaign-Urbana, Mattoon, Effingham, Flora, Harrisburg, and Metropolis. Between Gilman and Effingham, US45 closely follows along Interstate 57.
Information on US45 is broken down into 6 parts:
Wisconsin state line to Cook/Will County line (includes Chicago area)
Cook/Will County line to Ford/Champaign County line(includes Kankakee)
Ford/Champaign County line to Douglas/Coles County line (includes Champaign-Urbana and Tuscola)
Douglas/Coles County line to Effingham/Clay County line (includes Mattoon and Effingham)
Effingham/Clay County line to Gallatin/Saline County line (includes Fairfield and Flora)
Gallatin/Saline County line to Kentucky border (includes Harrisburg and Metropolis)
