Marion city, Illinois
Official LSAD Designation: Marion city • Census GEOID: 1746916
• Williamson County
Demographics & Population Profile
Population and demographics for Marion city.
| Demographic Variable | Estimate / Count | Margin of Error | Period | Source |
|---|---|---|---|---|
| Total Population (2025 PEP Estimate) | 17,148 | — | 2025 | Census |
| Median Age | 42.2 yrs | ±2 | 2020-2024 | Census ACS 5-Year 2024 |
| Total Households | 8,260 | ±329 | 2020-2024 | Census ACS 5-Year 2024 |
Source: U.S. Census Bureau (PEP, ACS 5-Year).