U.S. Route 6 closely follows the I-80 corridor in the State of Illinois. It enters the state from the west on I-74 in the Quad Cities, and exits in the east along I-80/I-94. It passes through the Quad Cities, Geneseo, Princeton, Spring Valley, LaSalle-Peru, Ottawa, Morris, Joliet, and some of Chicago's southern suburbs.
Information on US6 is broken into 3 sections:
Iowa state line to Bureau/Henry County line (includes Quad Cities and Geneseo)
Bureau/Henry County line to Grundy/Will County line (includes Princeton, LaSalle, Peru, and Morris)
Grundy/Will County line to Indiana state line (includes Joliet and the Chicago area)
