County Maps US

Randolph County, Illinois

A county in Illinois, ranked 47 of 102 by population.

CountyFIPS 17157

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

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Population
29,921
-170 (-0.6%) since 2020
Land area
575.4
square miles. A further 3.6% of the total area is water
Population density
52.0
people per square mile, computed rather than published
County seat
Chester
Seat of county government.
Established
1795
230 years ago
Largest city
Chester city
Population 6,847.

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 Randolph 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 Randolph 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 707 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 Randolph 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
Population29,92147th of 1021,449th of 3,144
Land area575.4 sq mi39th of 1021,724th of 3,144
Population density52.0 per sq mi44th of 1021,428th of 3,144
Median household income$68,13145th of 1021,329th of 3,143

Full data for Randolph County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population29,921Vintage 2025 Population Estimates
Population in 202030,091Vintage 2025 Population Estimates
2020 estimates base?30,165Vintage 2025 Population Estimates
Land area575.4 sq mi2025 Gazetteer Files
Water area21.7 sq mi2025 Gazetteer Files
Total area597.1 sq mi2025 Gazetteer Files
Population density?52.0 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$68,131American Community Survey 2020-2024 5-Year Estimates
Median home value$135,100American Community Survey 2020-2024 5-Year Estimates
Median age43.7American Community Survey 2020-2024 5-Year Estimates
Households11,945American Community Survey 2020-2024 5-Year Estimates
Housing units13,422American 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
-126
256 births, 382 deaths
Net migration
+177
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 7 areas bordering Randolph 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
Ste. Genevieve CountyMissouri29 mi18,689
Monroe CountyIllinois23 mi34,840
Perry CountyMissouri19 mi19,093
Perry CountyIllinois18 mi20,160
Jackson CountyIllinois13 mi52,501
St. Clair CountyIllinois11 mi250,708
Washington CountyIllinois6.0 mi13,564

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.