County Maps US

Iroquois County, Illinois

A county in Illinois, ranked 50 of 102 by population.

CountyFIPS 17075

Within Illinois
Iroquois County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Watseka, the county seat, located via the 2025 Census Gazetteer.

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Population
26,150
-817 (-3.0%) since 2020
Land area
1,117
square miles. A further 0.1% of the total area is water
Population density
23.4
people per square mile, computed rather than published
County seat
Watseka
Seat of county government.
Established
1833
192 years ago
Largest city
Watseka city
Population 4,510.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Iroquois County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Iroquois County, Illinois from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 711 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Iroquois County ranks

Position among the 102 counties of Illinois, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn IllinoisNationally
Population26,15050th of 1021,576th of 3,144
Land area1,117 sq mi3rd of 102563rd of 3,144
Population density23.4 per sq mi85th of 1022,109th of 3,144
Median household income$66,25554th of 1021,501st of 3,143

Full data for Iroquois County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population26,150Vintage 2025 Population Estimates
Population in 202026,967Vintage 2025 Population Estimates
2020 estimates base?27,066Vintage 2025 Population Estimates
Land area1,117 sq mi2025 Gazetteer Files
Water area1.6 sq mi2025 Gazetteer Files
Total area1,119 sq mi2025 Gazetteer Files
Population density?23.4 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$66,255American Community Survey 2020-2024 5-Year Estimates
Median home value$137,800American Community Survey 2020-2024 5-Year Estimates
Median age44.4American Community Survey 2020-2024 5-Year Estimates
Households11,443American Community Survey 2020-2024 5-Year Estimates
Housing units12,789American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-120
250 births, 370 deaths
Net migration
+51
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 5 areas bordering Iroquois County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Ford CountyIllinois45 mi13,216
Kankakee CountyIllinois32 mi105,525
Vermilion CountyIllinois22 mi71,259
Newton CountyIndiana19 mi14,188
Benton CountyIndiana17 mi8,883

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 102 counties of Illinois

Open the interactive Illinois county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.