County Maps US

Will County, Illinois

A county in Illinois, ranked 4 of 102 by population.

CountyFIPS 17197

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

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Population
712,253
+15,352 (+2.2%) since 2020
Land area
835.9
square miles. A further 1.6% of the total area is water
Population density
852
people per square mile, computed rather than published
County seat
Joliet
Seat of county government.
Established
1836
189 years ago
Largest city
Joliet city
Population 137,691 for the whole place, which extends beyond this county.

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 Will 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 Will 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 769 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 Will 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
Population712,2534th of 10299th of 3,144
Land area835.9 sq mi13th of 1021,004th of 3,144
Population density852 per sq mi5th of 102184th of 3,144
Median household income$109,9844th of 10298th of 3,143

Full data for Will County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population712,253Vintage 2025 Population Estimates
Population in 2020696,901Vintage 2025 Population Estimates
2020 estimates base?697,361Vintage 2025 Population Estimates
Land area835.9 sq mi2025 Gazetteer Files
Water area13.3 sq mi2025 Gazetteer Files
Total area849.2 sq mi2025 Gazetteer Files
Population density?852 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$109,984American Community Survey 2020-2024 5-Year Estimates
Median home value$319,600American Community Survey 2020-2024 5-Year Estimates
Median age39.1American Community Survey 2020-2024 5-Year Estimates
Households244,273American Community Survey 2020-2024 5-Year Estimates
Housing units254,278American 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
+1,841
6,947 births, 5,106 deaths
Net migration
+1,403
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 Will 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
Kankakee CountyIllinois43 mi105,525
Cook CountyIllinois41 mi5,194,625
Kendall CountyIllinois18 mi145,470
Grundy CountyIllinois18 mi54,052
DuPage CountyIllinois15 mi934,298
Lake CountyIndiana12 mi504,612

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

Side by side

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.