| Name | Monroe County |
| State | Illinois |
| FIPS Code | 17133 |
| County Seat | Waterloo |
| Timezone | Central Daylight Time (CDT) |
| Population (2024) | 35,144 |
| Population Growth Rate(2020-2024) | 0.54% |
| Majority Ethnicity | White 96.92% |
| Public School Majority Ethnicity | White 93% |
| Partisan Voting Index | Republican:+19 |
| Unemployment Rate (May 2026) | 3.3% |
| Sales Tax Rate (2025) | 7.5% |
| Area Code(s) | 618 / 314 / 557 |
| Race/Ethnicity | Percentage of Population (2023) |
|---|---|
| White | 96.92% |
| African American | 0.6% |
| Hispanic | 1.89% |
| Asian | 0.48% |
| Native American | 0.11% |
| Hawaiin/Pacific Islander | 0% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 93.34% |
| African American | 0.44% |
| Hispanic | 3.01% |
| Asian | 0.64% |
| Native American | 0.15% |
| Hawaiin/Pacific Islander | 0.03% |