Warren County, Illinois
Warren County is a county in Illinois. Its county FIPS code is 17187. Use the boundary map and neighboring areas below to check the jurisdiction you need.
- Official code
- 17187
- Representative coordinates
- 40.850441, -90.620223
- County type
- County
- County seat or government
- Monmouth
- Resident population, July 2025
- 16,222
- Land area
- 1,404.706 km²
- Water area
- 1.735 km²
- State
- Illinois
The representative point identifies this area. It is not a street address or a boundary survey.
Time zones in Warren County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| America/Chicago | UTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Listed zones overlap the mapped area. A point lookup can distinguish sides of a boundary. Your device’s zone may differ.
Census ZIP areas
61401 · 61410 · 61412 · 61415 · 61417 · 61423 · 61435 · 61447 · 61453 · 61462 · 61473 · 61474 · 61475 · 61478
These statistical areas overlap the boundary. They are not delivery assignments; confirm mailing details with USPS ZIP Code Lookup.
Official county information
Warren County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Cities, towns and communities
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
Areas sharing the mapped boundary
These areas touch this mapped boundary.
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Find the county at your current point, check its ZIP area, or find its physical time zone.