| Name | Warren County |
| State | Illinois |
| FIPS Code | 17187 |
| County Seat | Monmouth |
| Timezone | Central Daylight Time (CDT) |
| Population (2024) | 16,224 |
| Population Growth Rate(2020-2024) | -3.81% |
| Majority Ethnicity | White 82.82% |
| Public School Majority Ethnicity | White 67% |
| Partisan Voting Index | Republican:+12 |
| Unemployment Rate (May 2026) | 5.0% |
| Sales Tax Rate (2025) | 8% |
| Area Code(s) | 309 |
| Race/Ethnicity | Percentage of Population (2023) |
|---|---|
| White | 82.82% |
| African American | 2.73% |
| Hispanic | 10.54% |
| Asian | 2.35% |
| Native American | 1.17% |
| Hawaiin/Pacific Islander | 0.38% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 66.61% |
| African American | 3.79% |
| Hispanic | 20.83% |
| Asian | 2.84% |
| Native American | 0.09% |
| Hawaiin/Pacific Islander | 0.17% |