| Name | Saint Clair County |
| State | Illinois |
| FIPS Code | 17163 |
| County Seat | Belleville |
| Timezone | Central Daylight Time (CDT) |
| Population (2024) | 252,094 |
| Population Growth Rate(2020-2024) | -2.2% |
| Majority Ethnicity | White 63.72% |
| Public School Majority Ethnicity | White 46% |
| Partisan Voting Index | Democratic:+3 |
| Unemployment Rate (May 2026) | 5.1% |
| Area Code(s) | 618 |
| Race/Ethnicity | Percentage of Population (2023) |
|---|---|
| White | 63.72% |
| African American | 29.16% |
| Hispanic | 5.15% |
| Asian | 1.63% |
| Native American | 0.31% |
| Hawaiin/Pacific Islander | 0.03% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 45.56% |
| African American | 41.08% |
| Hispanic | 5.35% |
| Asian | 1.21% |
| Native American | 0.15% |
| Hawaiin/Pacific Islander | 0.16% |