County · Illinois · United States
St. Clair County ZIP codes
27 ZIP codes · 19 cities · FIPS 17163
Key facts
- State
- Illinois (IL)
- FIPS code
- 17163
- Population
- 254,777
- Median household income
- $70,178
- Median age
- 39.5
- Land area
- 657.7 sq mi (1,703.5 km²)
- Population density
- 387 / sq mi
- Area codes
- 309, 618, 730
Cities and ZIP codes in St. Clair County (19)
About this page
County figures are Census county-level values (ACS 5-year); the ZIP list shows the ZIPs whose primary county this is — a ZIP on a border can also serve neighbouring counties.
Sources: U.S. Census Bureau (2020 county relationship file, ACS 5-year) · GeoNames. Methodology.