Illinois was the first Route 66 state encountered by westbound travelers leaving Chicago.
Route 66 began in the Chicago area and crossed Illinois from the northeastern part of the state toward the Mississippi River. Its Illinois alignment passed through communities including Joliet, Pontiac, Bloomington-Normal, Springfield, Litchfield, and Edwardsville before continuing into Missouri.
Missouri was the next state westbound, followed by a short section of Kansas, then Oklahoma. That sequence is a common source of confusion because Missouri’s St. Louis area was an important gateway and because Route 66’s overall identity is often associated with the Southwest.
Illinois retains many recognizable remnants, including old gas stations, diners, murals, museums, and roadside structures. The Illinois Route 66 corridor is especially important because it preserves the route’s Midwestern beginning rather than only its desert landscapes.