Lake County, Illinois

County seat: Waukegan · Population 719,339 (2025) · 444 sq mi

Lake County is the 3rd most populous of Illinois's 102 counties, with 719,339 people (2025 estimate). Its county seat is Waukegan. It is part of the Northeast region, one of the 10 Illinois economic development regions (DCEO). The map shows its 52 cities and towns and the 6 neighboring counties.

Map of Lake County, Illinois with cities, towns and the county boundary
Lake County, Illinois with its cities and towns, unincorporated communities (CDPs) and neighboring counties. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
Download PDF (Letter) 217 KBPNG image 151 KBIllinois county map

Lake County facts

County seat
Waukegan
Population (2025 estimate)
719,339 +0.7% since 2020
Land area
444 sq mi 61st largest of 102
Water area
925 sq mi
Population density
1,621 per sq mi
Established
1839
Same name
One of 12 Lake Counties in the US
Named after
Lake Michigan one of the Great Lakes of North America
Largest city
Waukegan 87,940
Median household income
$110,416
Cities and towns
52 plus 9 CDPs
ZIP codes
36
Time zone
Central
FIPS code
17097

Cities and towns in Lake County

Lake County has 52 incorporated cities, towns and villages. Populations count the people living inside Lake County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
Waukegan (county seat)City87,940
North ChicagoCity34,050
MundeleinVillage32,680
Highland ParkCity30,767
GurneeVillage30,458
Buffalo GroveVillage29,332Cook County
Round Lake BeachVillage26,902
Vernon HillsVillage26,825
ZionCity24,447
GrayslakeVillage21,140
LibertyvilleVillage20,701
Lake ZurichVillage19,868
Lake ForestCity19,731
DeerfieldVillage19,157Cook County
Round LakeVillage18,526
AntiochVillage15,000
LindenhurstVillage14,810
Beach ParkVillage14,114
WaucondaVillage13,993
Fox LakeVillage10,209McHenry County
Hawthorn WoodsVillage9,679
Lake VillaVillage8,692
Long GroveVillage8,343
LincolnshireVillage7,963
Park CityCity7,893
Round Lake ParkVillage7,844
VoloVillage6,805
Winthrop HarborVillage6,525
Lake BluffVillage5,563
HighwoodCity5,323
Lake BarringtonVillage5,130
BarringtonVillage4,846Cook County
KildeerVillage4,683
Green OaksVillage4,082
LakemoorVillage3,885McHenry County
RiverwoodsVillage3,766
Deer ParkVillage3,627Cook County
HainesvilleVillage3,501
WadsworthVillage3,488
Island LakeVillage3,364McHenry County
North BarringtonVillage3,125
Round Lake HeightsVillage2,580
BannockburnVillage1,308
Tower LakesVillage1,201
Third LakeVillage1,103
Barrington HillsVillage597Cook, Kane and McHenry counties
MettawaVillage567
Indian CreekVillage531
Port BarringtonVillage531McHenry County
Fox River GroveVillage505McHenry County
Old Mill CreekVillage162
WheelingVillage0Cook County

Unincorporated communities (CDPs)

Census-designated places are communities without their own city government; the county provides their services.

CommunityPopulationAlso in
Gages Lake10,819
Grandwood Park5,262
Long Lake3,307
Fox Lake Hills2,399
Venetian Village2,334
Channel Lake2,052
Forest Lake1,865
Knollwood1,864
Lake Catherine968

ZIP codes in Lake County

36 ZIP codes reach into Lake County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of Lake County, 2020–2025

Lake County grew by 4,945 people (+0.7%) between April 2020 and July 2025: 6,949 more births than deaths and a net loss of 2,557 people from migration.

Year (July 1)Population
2020713,377
2021713,775
2022712,412
2023713,653
2024718,490
2025719,339

Neighboring counties

Printable Lake County map

The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.

Paste this code to embed the map on your site:

Sources

Back to the Illinois county map with all 102 counties. Found an error? Tell us.