Illinois State Route 203 is a north-south highway in Southwestern Madison County. It runs along a old alignment of Illinois State Route 203. IL St Rt 203 passes through the following towns in Madison County. Madison
Granite City
IL St Rt 203 is not multi-plexed in Madison County. IL St Rt 203 intersects the following highways in Madison County. Illinois State Route 162, at Granite City.
NB IL St Rt 203 at the Madison/St. Clair County Line. NB IL St Rt 203 on the south end of Madison. SB IL St Rt 203 in Madison. A guide marker in Madison. NB IL St Rt 203 east of Staunton Street in Madison. NB IL St Rt 203 in Madison. A BGS on NB IL St Rt 203 in Madison. SB IL St Rt 203 in Granite City. NB IL St Rt 203 north of IL St Rt 162. A Madison County mile marker. SB IL St Rt 203 south of I-270. (August, 2014) SB IL St Rt 203 south of I-270. (May, 2025) A BGS on EB I-270. A BGS on WB I-270. A junction marker on SB Old U.S. Rt. 66. The northern end marker. The northern end of IL St Rt 203. (July, 2017)
