St. Clair County, Illinois
St. Clair County is the oldest county in the U.S. state of Illinois. According to the 2020 census, it had a population of 257,400,[1] making it the ninth-most populous county in Illinois. Its county seat is Belleville.[2] The county was founded in 1790, before the establishment of Illinois as a state.
| St. Clair County, Illinois | |
| Seal of St. Clair County, Illinois | |
| Map | |
| Map of Illinois highlighting St. Clair County Location in the state of Illinois | |
 Illinois's location in the U.S. | |
| Statistics | |
| Founded | 1790 |
|---|---|
| Seat | Belleville |
| Largest City | Belleville |
| Area - Total - Land - Water |
674 sq mi (1,746 km²) 658 sq mi (1,704 km²) 16 sq mi (41 km²), 2.4 |
| Population - Density |
|
| Time zone | Central: UTC-6/-5 |
| Website: www.co.st-clair.il.us | |
| Named for: Arthur St. Clair | |
St. Clair County, Illinois Media
- Victorian home restored.JPG
House in Lebanon, Il historic district
- Mermaid House Hotel.JPG
Mermaid House Hotel, Lebanon, Illinois
- Map of the East St. Louis and Suburban Company c 1912.png
Map of the East St. Louis and Suburban Company c 1912
St. Clair County as it was re-established in 1809. This diagonal border line had been drawn by the Indiana Territorial government in 1803.
- St. Clair County Illinois 1812.png
St. Clair County between 1812 and 1813
- St. Clair County Illinois 1813.png
St. Clair County between 1813 and 1816
- St. Clair County Illinois 1816.png
St. Clair County between 1816 and 1818
St. Clair County between 1818 and 1825
- St. Clair County Illinois 1825.png
St. Clair County between 1825 and 1827
- St. Clair County Illinois 1827.png
St. Clair County from 1827 to present
References
- ↑ "QuickFacts: St. Clair County, Illinois". United States Census Bureau. Retrieved August 14, 2023.
- ↑ "Find a County". National Association of Counties. Retrieved 2011-06-07.
