Federal Route 51 is a north-south route running down the middle of the State of Illinois from Wisconsin to Kentucky. From Bloomington northward, US51 runs along Interstate 39 through north-central Illinois, passing the Rockford area. South of Bloomington, US51 passes through the Decatur, Vandalia, and Carbondale areas.
Wisconsin State line to Ogle/Lee County line (includes Rockford)
Ogle/Lee County line to Marshall/Woodford County line (includes LaSalle-Peru area)
Shelby/Fayette County line to Washington/Perry County line (includes Vandalia and Centralia)
Washington/Perry County line to Kentucky border(includes Carbondale, Cairo, and DuQuoin)
