Illinois · FIPS 17187 · County seat: Monmouth
Warren County, IL GIS & Parcel Viewer
Parcel lookups for Warren County start at Parcel_App for Warren County. This page gives you that official link, notes on how the viewer works, and links to the counties next door.
Open the Warren County parcel map ↗
Opens warrenco-094.maps.arcgis.com in a new tab. We link out and never embed or copy parcel data.
Warren County at a glance
| Official map | Parcel_App for Warren County |
|---|---|
| Type | County-run map |
| Website | warrenco-094.maps.arcgis.com |
| Access | Free, no login (checked Oct 2026) |
| County seat | Monmouth |
| Population | 16,185 (2023 Census Bureau estimate) |
| Land area | 542 sq mi |
| FIPS code | 17187 |
About the official source
Warren County runs this viewer (directly or through a contracted vendor), which makes it the closest thing to the source for local parcel lines. As of our October 2026 test, anyone could open it without signing in or paying.
How to use the Warren County viewer
- Open the official link. The viewer is built with ArcGIS Web AppBuilder; if a disclaimer pops up, accept it to continue.
- Use the search widget, usually in the upper left, to find a street address or parcel ID.
- Click a parcel to open its info window.
- The widget bar holds extras such as the layer list, basemap switcher, measure and print tools.
Have a tax bill handy? The parcel or account number on it is usually the fastest way to search.
Warren County by the numbers
Census Bureau figures put Warren County at about 16,185 people (2023 estimate) on roughly 542 square miles of land, which is about 30 residents per square mile. Among Illinois's 102 counties, it is the 65th largest by population. Monmouth serves as the county seat.
Counties next to Warren County
Parcels close to the edge of Warren County can fall in the next county over. Neighboring counties:
Before you rely on the lines
Keep in mind that a GIS parcel layer is a tax map, not a survey. For exact boundaries, look at the recorded deed and plat or hire a licensed land surveyor.