County Maps US

Clinton County, Illinois

A county in Illinois, ranked 35 of 102 by population.

CountyFIPS 17027

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

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Population
37,128
+213 (+0.6%) since 2020
Land area
473.9
square miles. A further 5.8% of the total area is water
Population density
78.3
people per square mile, computed rather than published
County seat
Carlyle
Seat of county government.
Established
1824
201 years ago
Largest city
Breese city
Population 4,602.

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 Clinton 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 Clinton 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 800 by 612 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 Clinton 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
Population37,12835th of 1021,264th of 3,144
Land area473.9 sq mi58th of 1022,175th of 3,144
Population density78.3 per sq mi30th of 1021,099th of 3,144
Median household income$86,58812th of 102386th of 3,143

Full data for Clinton County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population37,128Vintage 2025 Population Estimates
Population in 202036,915Vintage 2025 Population Estimates
2020 estimates base?36,904Vintage 2025 Population Estimates
Land area473.9 sq mi2025 Gazetteer Files
Water area29.2 sq mi2025 Gazetteer Files
Total area503.1 sq mi2025 Gazetteer Files
Population density?78.3 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$86,588American Community Survey 2020-2024 5-Year Estimates
Median home value$192,400American Community Survey 2020-2024 5-Year Estimates
Median age41.5American Community Survey 2020-2024 5-Year Estimates
Households14,570American Community Survey 2020-2024 5-Year Estimates
Housing units15,765American 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
-17
378 births, 395 deaths
Net migration
+55
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 6 areas bordering Clinton 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
Washington CountyIllinois61 mi13,564
Bond CountyIllinois19 mi16,959
St. Clair CountyIllinois17 mi250,708
Marion CountyIllinois16 mi36,382
Madison CountyIllinois12 mi263,110
Fayette CountyIllinois6.3 mi20,790

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.