Illinois Route 203
| Nameoki Road | ||||
IL 203 highlighted in red | ||||
| Route information | ||||
| Maintained by IDOT | ||||
| Length | 9.51 mi (15.30 km) | |||
| Existed | 1964–present | |||
| Major junctions | ||||
| South end | Collinsville Road in Fairmont City | |||
| I-55 / I-70 / US 40 in Fairmont City | ||||
| North end | I-270 in Granite City | |||
| Location | ||||
| Country | United States | |||
| State | Illinois | |||
| Counties | St. Clair, Madison | |||
| Highway system | ||||
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Illinois Route 203 (IL 203) is a 9.51-mile-long (15.30 km) north–south state highway in the southwestern part of the U.S. state of Illinois. It travels from just south of I-55/I-70/US 40 around Gateway International Raceway at Collinsville Road (former US 40) in Fairmont City, north to I-270 near Pontoon Beach. IL 203 is a former segment of US 66.