Saint Clair County Illinois is covered by a total of 35 ZIP Codes. There are 11 ZIP Codes in Saint Clair County that extend into adjacent counties (Clinton County, Madison County, Monroe County, and Washington County). Of the ZIP codes within or partially within Saint Clair County there are 29 Standard ZIP Codes and 5 PO Box ZIP Codes.
Click on the ZIP Codes in the interactive map to view more information. The map control in the upper right corner can be used to toggle map layers on and off. The red outline is the border of Saint Clair County and can be turned on and off. Each type of postal code can also be turned on and off.