County Maps US

Lake County, Illinois

A county in Illinois, ranked 3 of 102 by population.

CountyFIPS 17097

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

Download SVGFull Illinois map downloads

Population
719,339
+5,962 (+0.8%) since 2020
Land area
443.7
square miles. A further 67.6% of the total area is water
Population density
1,621
people per square mile, computed rather than published
County seat
Waukegan
Seat of county government.
Established
1839
186 years ago
Largest city
Waukegan city
Population 87,940.

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 Lake 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 Lake 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 762 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 Lake 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
Population719,3393rd of 10298th of 3,144
Land area443.7 sq mi61st of 1022,289th of 3,144
Population density1,621 per sq mi3rd of 10299th of 3,144
Median household income$110,4163rd of 10295th of 3,143

Full data for Lake County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population719,339Vintage 2025 Population Estimates
Population in 2020713,377Vintage 2025 Population Estimates
2020 estimates base?714,394Vintage 2025 Population Estimates
Land area443.7 sq mi2025 Gazetteer Files
Water area924.7 sq mi2025 Gazetteer Files
Total area1,368 sq mi2025 Gazetteer Files
Population density?1,621 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$110,416American Community Survey 2020-2024 5-Year Estimates
Median home value$345,700American Community Survey 2020-2024 5-Year Estimates
Median age39.1American Community Survey 2020-2024 5-Year Estimates
Households258,455American Community Survey 2020-2024 5-Year Estimates
Housing units270,618American 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
+1,330
6,424 births, 5,094 deaths
Net migration
-506
More people moved out than moved in.

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

The 6 areas bordering Lake 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
Kenosha CountyWisconsin60 mi168,448
Cook CountyIllinois56 mi5,194,625
McHenry CountyIllinois24 mi317,751
Van Buren CountyMichigan13 mi76,071
Berrien CountyMichigan6.0 mi152,444
Allegan CountyMichigan5.4 mi123,188

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.