County GIS · State lines · October 19, 2026
Illinois–Indiana Border Counties: Parcel Maps on Both Sides
All 23 counties on the Illinois–Indiana line, with seats, 2023 populations and a link to each official parcel map, plus what changes at the state line.
Looking for the counties on the Illinois–Indiana border and their parcel maps? According to the Census Bureau's county adjacency file, 12 Illinois counties touch 11 Indiana counties along the line. Each one keeps its own property records and its own parcel viewer, so land near the line often means checking two counties in two states.
Below you will find every county on both sides of the line, who borders whom, and what changes when you cross from one records office to the other.
Illinois–Indiana border at a glance
- Counties on the line: 23 (12 in Illinois, 11 in Indiana)
- With a verified public parcel viewer in our directory: 23 of 23
- Residents, 2023 estimates: about 6,085,076 on the Illinois side and 943,481 on the Indiana side
- Most populous on each side: Cook County, IL (5,087,072) and Lake County, IN (500,598)
- Largest by land area: Iroquois County, IL (1,117 sq mi) and Knox County, IN (516 sq mi)
Illinois counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Clark County | Marshall | 501 | 15,088 | Beacon (Schneider Geospatial) |
| Cook County | Chicago | 945 | 5,087,072 | county web map |
| Crawford County | Robinson | 444 | 18,300 | Beacon (Schneider Geospatial) |
| Edgar County | Paris | 623 | 16,334 | BHA Maps |
| Gallatin County | Shawneetown | 323 | 4,670 | WTH GIS |
| Iroquois County | Watseka | 1,117 | 26,136 | BHA Maps |
| Kankakee County | Kankakee | 676 | 105,940 | ArcGIS Experience Builder |
| Lawrence County | Lawrenceville | 372 | 14,813 | BHA Maps |
| Vermilion County | Danville | 898 | 71,652 | BHA Maps |
| Wabash County | Mount Carmel | 223 | 10,942 | BHA Maps |
| White County | Carmi | 495 | 13,401 | ArcGIS Experience Builder |
| Will County | Joliet | 836 | 700,728 | county web map |
Indiana counties on the line
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| Benton County | Fowler | 406 | 8,729 | Beacon (Schneider Geospatial) |
| Gibson County | Princeton | 487 | 32,904 | Beacon (Schneider Geospatial) |
| Knox County | Vincennes | 516 | 36,070 | Beacon (Schneider Geospatial) |
| Lake County | Crown Point | 499 | 500,598 | ArcGIS Experience Builder |
| Newton County | Kentland | 402 | 13,960 | Beacon (Schneider Geospatial) |
| Porter County | Valparaiso | 418 | 175,335 | ArcGIS Experience Builder |
| Posey County | Mount Vernon | 409 | 25,040 | WTH GIS |
| Sullivan County | Sullivan | 447 | 20,757 | Beacon (Schneider Geospatial) |
| Vermillion County | Newport | 257 | 15,417 | WTH GIS |
| Vigo County | Terre Haute | 404 | 106,153 | Beacon (Schneider Geospatial) |
| Warren County | Williamsport | 365 | 8,518 | WTH GIS |
Which counties face each other
The Census adjacency file pairs counties that share a boundary. Use it to find the county across the line from the one you know:
- Clark County, IL borders Sullivan County, IN, Vigo County, IN
- Cook County, IL borders Lake County, IN, Porter County, IN
- Crawford County, IL borders Knox County, IN, Sullivan County, IN
- Edgar County, IL borders Vermillion County, IN, Vigo County, IN
- Gallatin County, IL borders Posey County, IN
- Iroquois County, IL borders Benton County, IN, Newton County, IN
- Kankakee County, IL borders Lake County, IN, Newton County, IN
- Lawrence County, IL borders Knox County, IN
- Vermilion County, IL borders Benton County, IN, Vermillion County, IN, Warren County, IN
- Wabash County, IL borders Gibson County, IN, Knox County, IN
- White County, IL borders Gibson County, IN, Posey County, IN
- Will County, IL borders Lake County, IN
What changes when you cross the line
- Different viewers. On the Illinois side the official maps run on: BHA Maps (5); Beacon (Schneider Geospatial) (2); county web map (2); ArcGIS Experience Builder (2); WTH GIS (1). On the Indiana side: Beacon (Schneider Geospatial) (6); WTH GIS (3); ArcGIS Experience Builder (2). Search boxes, parcel ID formats and the details shown in pop-ups will differ.
- Different records offices. Deeds, plats and tax bills are kept by the county where the parcel sits.
- Different rules. Zoning, septic permits and property tax are set locally and by each state, so check with the county on the side where you plan to build or buy.
Researching a tract that crosses the line
- Find the parcel in both counties' viewers. Each side will show only its own piece, with its own parcel number.
- Pull the recorded deed from each county's register or recorder, since each county records only the land inside its own boundary.
- Expect two tax bills, one from each county, and check each state's rules for homestead or farm exemptions.
- For a sale, a fence or a building permit, hire a licensed surveyor familiar with the line; tax-map lines are drawings, not surveys.
A quick way to check which side a spot is on
Tap the spot on the Platbookmapper Land Map. Its land report names the county and links straight to that county's parcel viewer, plus FEMA flood, USGS elevation, USDA soil and wetland results.
Related guides
More: Illinois counties · Indiana counties
Sources
- U.S. Census Bureau county adjacency file, used for which counties share the line.
- U.S. Census Bureau Gazetteer files, 2020 county land area.
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2023 (July 1, 2023 estimates)
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 19, 2026) for each county's official parcel viewer.
- County seats: Wikidata (county seat property), cross-checked against Census place names.