Will County, Illinois population

County or county equivalent · Official geographic code 17197

712,253

· Annual resident population estimate

U.S. Census Bureau · Population Estimates Program · Vintage 2025

+3,273 residents (+0.46%) since July 1, 2024.

Will County had an estimated 712,253 residents on July 1, 2025, the 4th most populous of 102 counties and county equivalents in Illinois. Its population grew 0.46% between July 2024 and July 2025, compared with +0.13% for Illinois and +0.52% for the United States.

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Population change, 2020–2025
+15,352July 1 to July 1 · +2.20%
Land-area density, 2025
852.1People per square mile · 2025 land area
Rank in Illinois, 2025
4 of 10299 of 3,144 nationally

Will County population history

Open historical explorer

The six July 1 estimates in the table belong to one consistent Vintage 2025 series. The Census Bureau revises earlier years when it releases a new vintage; a figure from an older publication may differ from the value below.

Will County population, 2010–2025: 2010–2020 intercensal estimates (2020 boundaries) and Vintage 2025 estimates (2025 boundaries) 716.4k694.4k672.4k 2010201520202025

Vintage 2025, July 1, 2020–2025 Intercensal, 2010–2020

The highest observed population in this annual series was 712,253 in 2025. This is a peak within 2020–2025 coverage, not an all-time record.

Will County, Illinois: July 1 annual population estimates, Vintage 2025
Reference datePopulationAnnual change
July 1, 2020696,901—
July 1, 2021699,920+3,019
July 1, 2022699,112-808
July 1, 2023703,872+4,760
July 1, 2024708,980+5,108
July 1, 2025712,253+3,273
Why is the April 2020 estimates base different from a census count?

The PEP estimates base here is 697,361 residents on April 1, 2020. It incorporates the Census Bureau’s corrections and geographic revisions and serves as the starting point for this annual series. It is not labeled an original 2020 census count. The chart starts at July 1, 2020, so its five-year change uses two July observations. Read about measurement types.

Will County population by year, 2010–2020

From the April 2010 estimates base to the April 2020 census count, Will County gained 18,785 residents (+2.8%). These Census Bureau intercensal estimates use 2020 boundaries and were released in November 2024.

Will County: 2010–2020 intercensal population estimates and April 1, 2020 census count, 2020 boundaries
DatePopulationAnnual change
April 1, 2010 · estimates base677,590—
July 1, 2010679,003—
July 1, 2011681,682+2,679
July 1, 2012684,025+2,343
July 1, 2013685,980+1,955
July 1, 2014688,078+2,098
July 1, 2015689,476+1,398
July 1, 2016692,678+3,202
July 1, 2017695,399+2,721
July 1, 2018696,672+1,273
July 1, 2019696,609-63
April 1, 2020 · census count696,375—

The April 2020 census count (696,375) and the Vintage 2025 April 2020 base (697,361) differ by 986. The gap comes from boundary changes and the Census Bureau’s revised 2020 base, not population change, so measure growth within one series. Source and download

Growth and density

Between July 1, 2020 and July 1, 2025, Will County gained 15,352 residents, a 2.20% increase. The annualized change over these five elapsed years was +0.44%. Annualized change is a summary of the interval; it does not imply that the population changed at that rate in every year.

The 2025 Gazetteer reports 835.91 square miles of land. Dividing the July 1, 2025 population by that compatible land area gives 852.1 people per square mile. Water area is excluded. Density depends on geographic boundaries. It describes this entire geography, rather than a typical neighborhood or built-up area.

Calculations use unrounded source values. Population counts are displayed as integers, percentages to two decimals and density to one decimal. Calculation methods · Growth calculator

Components of population change

The published components cover July 1, 2024 through June 30, 2025. Natural change equals births minus deaths. Net migration is arrivals minus departures; it does not establish why people moved.

Natural change
+1,841
Net domestic migration
+207
Net international migration
+1,196
Residual
+29
Source-published components, annual interval ending June 30, 2025
ComponentPeople
Births6,947
Deaths5,106
Natural change+1,841
Net domestic migration+207
Net international migration+1,196
Residual+29
Total population change+3,273

Reconciliation: natural change + net domestic migration + net international migration + residual = +3,273. Births and deaths are already included in natural change and must not be added again. Source: co-est2025-alldata.csv; Vintage 2025.

How Will County compares

Growth rates below use the same Vintage 2025 series for every row, so they can be compared directly. A county’s rate reflects all of its towns and unincorporated areas together.

Population and growth compared with larger geographies, Vintage 2025
GeographyPopulation · 2025Growth · 2024–25Growth · 2020–25
Will County712,253+0.46%+2.20%
Illinois12,719,141+0.13%-0.60%
United States341,784,857+0.52%+3.08%

Will County demographics: age, race and income

The median age in Will County is 39.1 years, compared with 39.0 in Illinois. 37.5% of adults 25 and older hold a bachelor’s degree or higher, and the median household income is $109,984. About 7.3% of residents live below the poverty level, and 13.5% were born outside the United States.

These are American Community Survey 5-year estimates for 2020–2024. They describe the 60 months ending in December 2024, come from a sample survey with the margins of error shown, and are separate from the July 1, 2025 population estimate above.

Will County population characteristics, ACS 2020–2024 5-year estimates with 90 percent margins of error
CharacteristicWill CountyMarginIllinoisU.S.
Age and sex
Median age39.1±0.239.038.9
Under 18 years23.6%±0.321.8%22.0%
65 years and over14.6%±0.317.0%17.2%
Female50.1%±<0.150.6%50.5%
Race and Hispanic origin
Hispanic or Latino (any race)19.8%±<0.118.8%19.3%
White alone, not Hispanic58.6%±0.158.1%57.4%
Black alone, not Hispanic11.6%±0.113.3%11.9%
Asian alone, not Hispanic6.3%±0.15.9%5.9%
American Indian and Alaska Native, not Hispanic0.1%±<0.10.1%0.5%
Native Hawaiian and Pacific Islander, not Hispanic0.0%±<0.10.0%0.2%
Some other race, not Hispanic0.4%±0.10.4%0.6%
Two or more races, not Hispanic3.4%±0.23.4%4.3%
Born outside the United States13.5%±0.414.7%14.1%
Households and education
Households244,273±8355,036,449129,227,496
Average household size2.84±0.012.462.53
Bachelor’s degree or higher, age 25+37.5%±0.737.8%35.7%
Income and poverty
Median household income$109,984±$1,819$83,390$80,734
Below the poverty level7.3%±0.411.8%12.5%

Margins are 90% margins of error. Percentages are computed from published Summary File counts with Census Bureau margin formulas. ACS survey population: 701,462; 2024 boundaries. Source and download

Geographic context

County equivalents include parishes, boroughs, census areas, independent cities, DC and Connecticut planning regions where represented by Census. The places listed below are whole-city observations and can extend into other counties. Summing them will not reproduce this county total.

Resident population, July 1, 2025; change since July 1, 2024. PEP Vintage 2025.
PlacePopulation · 2025Change · 2024–25Growth · 2024–25People / sq. mi.
AuroraIllinois · Incorporated place · 1703012181,505+595+0.33%4,011.5
NapervilleIllinois · Incorporated place · 1751622153,114+566+0.37%3,889.3
JolietIllinois · Incorporated place · 1738570152,241+337+0.22%2,297.7
BolingbrookIllinois · Incorporated place · 170713374,803+33+0.04%2,997.3
Orland ParkIllinois · Incorporated place · 175664057,954-33-0.06%2,629.2
Tinley ParkIllinois · Incorporated place · 177548455,140+280+0.51%3,408.7
PlainfieldIllinois · Incorporated place · 176028750,043+1,218+2.49%1,914.5
RomeovilleIllinois · Incorporated place · 176544241,281-169-0.41%2,127.3
OswegoIllinois · Incorporated place · 175688739,948+1,210+3.12%2,463.9
WoodridgeIllinois · Incorporated place · 178324534,028+83+0.24%3,532.7

Showing 10 of 37 related records.

Illinois population · State city directory · City proper versus county versus metro

Illinois counties and county equivalents with nearby population ranks

Neighboring 2025 population ranks within Illinois. Similar population does not imply similar density, boundaries or demographics.

Resident population, July 1, 2025; change since July 1, 2024. PEP Vintage 2025.
PlacePopulation · 2025Change · 2024–25Growth · 2024–25People / sq. mi.
DuPage County934,298+1,647+0.18%2,849.4
Lake County719,339+849+0.12%1,621.3
Kane County525,757+2,327+0.44%1,012.3
McHenry County317,751+2,021+0.64%526.6

Source, citation and downloads

U.S. Census Bureau, Population Estimates Program, Vintage 2025, co-est2025-alldata.csv, variable POPESTIMATE2025; Will County, Illinois, geographic code 17197; resident population 712,253 on July 1, 2025; boundaries January 1, 2025. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/counties/totals/co-est2025-alldata.csv. Retrieved September 30, 2026. US Population Data snapshot pep-2025-r1, transformation 1.

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