Cook County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 1st-largest in Illinois
The population of Cook County, Illinois is 5,185,812 as of the 2023 American Community Survey, making it the 1st-largest county in Illinois. The median household income is $81,797, the median home value is $305,200, and the median age is 37.8.
The population of Cook County has declined 0.3% since 2010 (5,198,977 → 5,182,617), a -0.02% annualized rate.
5,185,812
Population
-0.02%
Annual growth
5488
People / sq mi
$81,797
Median Income
$305,200
Median Home Value
Cook County covers 945 sq mi of land at 5488.1 people per square mile.
About Cook County, IL
What distinguishes Cook County is density: among the most densely settled of US counties, around 5,488 people per square mile. With 5,185,812 residents, Cook County is a county in Illinois. It is the #1-largest of all counties in Illinois nationally.
Households take in a median $81,797, comfortably near the US median of $78,538. About 9.8% of residents live below the federal poverty level, below the national 12.4%. Home values run above average at $305,200, with typical rent around $1,381.
The population is unusually well-credentialed for US counties — 41.9% of adults have a four-year degree, above the national 35.0%. An unusually large 16.5% of workers are remote, above the national 14.0%, and the average commute runs about 32 minutes each way.
That density explains much of the rest of the profile in Cook County: denser places lean toward renting, shorter commutes by transit, and a younger working-age mix.
Cook County Population History (2010-2024)
The county of Cook County had a population of 5,198,977 in 2010 and 5,182,617 in 2024, a -0.3% growth over 14 years. The peak was 5,267,072 in 2020. Average annual growth rate: -0.02%.
5,182,617
Population (2024)
5,198,977
Population (2010)
5,267,072
Peak (2020)
-0.02%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 5,198,977 |
| 2011 | 5,219,636 |
| 2012 | 5,239,105 |
| 2013 | 5,252,513 |
| 2014 | 5,254,108 |
| 2015 | 5,243,371 |
| 2016 | 5,223,386 |
| 2017 | 5,199,582 |
| 2018 | 5,171,007 |
| 2019 | 5,145,326 |
| 2020 | 5,267,072 |
| 2021 | 5,185,134 |
| 2022 | 5,133,106 |
| 2023 | 5,142,522 |
| 2024 | 5,182,617 |
Race & Ethnicity
| White | 46.4% |
| Black or African American | 22.5% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.7% |
| Two or More Races | 0.0% |
Age & Sex
37.8
Median Age
51.2%
Female
48.8%
Male
15.6%
Age 65+
Age Distribution
Children (under 15): 17.6% · Seniors (65+): 15.6%
Income & Poverty
| Median household income | $81,797+$95 vs state |
| Mean household income | $117,699 |
| Per-capita income | $47,801 |
| Poverty rate | 9.8%+1.6% vs state |
| Unemployment rate | 4.5% |
| Employment-to-population | 61.6% |
Top Industries by Employment
The largest employment sector in Cook County is professional & business services, accounting for 23.5% of workers.
How residents commute
13.0%
Drive alone
3.9%
Carpool
56.2%
Public transit
16.5%
Work from home
31.9 min
Avg commute
Housing
$305,200+$54,700 vs state
Median home value
$1,381
Median rent
57.5%
Homeownership rate
2,270,349
Total housing units
91.8%
Occupied
8.2%
Vacant
42.5%
Renter-occupied
Social & access
91.0%
With health insurance
94.4%
With broadband internet
15.7%
Foreign-born
3.3%
Veterans (18+)
11.2%
With a disability
64.5%
Speak language other than English at home
Education
88.3%
High School+
41.9%
Bachelor's+
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County rankings
Common questions about Cook County, IL
Frequently Asked Questions
Cook County, Illinois has a population of 5,185,812 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 1st-largest county in Illinois. Population density is 5488 people per square mile.
The population of Cook County has declined 0.3% since 2010 (5,198,977 → 5,182,617), a -0.02% annualized rate.
The median household income in Cook County, Illinois is $81,797, with mean (average) household income of $117,699 and per-capita income of $47,801. 9.8% of residents live below the federal poverty level.
In Cook County, the largest racial and ethnic groups are White (46.4%), Black or African American (22.5%), Hispanic or Latino (1.7%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Cook County, Illinois is 37.8 years. Residents are 51.2% female and 48.8% male.
The median home value in Cook County is $305,200 and median monthly rent is $1,381. 57.5% of occupied housing units are owner-occupied. The county has 2,270,349 total housing units, 8.2% of which are vacant.
The largest employment sector in Cook County, Illinois is professional, scientific, and management services, employing 23.5% of workers. The unemployment rate is 4.5%.
Chicago is among the largest cities associated with Cook County, Illinois, with a population of 2,707,648.
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.