What is the largest city in Cook County, IL?

Chicago is the largest city or town in Cook County, with about 2,711,226 residents.

How many ZIP codes are in Cook County?

Cook County includes 166 ZIP Code Tabulation Areas, including 60004, 60005, 60007, 60008, 60016.

What is the population of Cook County, IL?

About 5,182,090 people live in Cook County, based on American Community Survey 5-year estimates.

What counties border Cook County?

Cook County borders DuPage County, Lake County, Will County, Kane County, Lake County, IN, McHenry County.

Cook County, IL: Cities, ZIP Codes & Local Data

Population

5,182,090

Land area

945sq mi

People per sq mi

5,484

ZIP codes

166

Cook County at a glance

Cook County is about 24 times as dense as Illinois as a whole.
No county in Illinois has more people.
The median household income is $83,498, close to the Illinois median.
A typical owner-occupied home is valued at $324,500 (23% above Illinois) and median rent is $1,435 a month.
Its largest cities are Chicago (2.7 million), Cicero (82,797) and Schaumburg (76,868).

Local data for Cook County, IL

Counts from official public data

Housing and community stats

Cook County, IL, American Community Survey 2020-2024

Full profile

Median household income

$83,498

Poverty rate

13.5%

Median home value

$324,500

Prices +5.5% in a year

Median rent

$1,435/mo

Homeownership

57.7%

Bachelor's or higher

42.7%

Median age

38.0

Average commute

31.5 min

Largest reported origins and ancestries: Mexican Americans (1,043,055), German Americans (464,737), Irish Americans (432,999).

Home values and rents Income, education and commute

Economy and federal money

Jobs, income, federal spending and pandemic loans

Details

Unemployment rate

5.9%

Aug 2026, +1.2 pts in a year

Average annual pay

$90,477

2,594,810 jobs, 2025

Income per person

$79,964

BEA, 2024

Federal spending

$35.97B

FY 2026, $6,818 per person

PPP loans

$18.77B

330,204 loans, 1,848,967 jobs reported

Campaign donations

$130M

Itemized, 2026 cycle

Economy Federal spending PPP loans

How people get to work

Cook County, IL, workers 16 and older. American Community Survey 5-year estimates

Drove alone54.8%
Carpooled7.7%
Public transit11.8%
Walked4.0%
Bicycle0.9%
Taxi, ride-hailing, motorcycle or other1.8%
Worked from home18.9%

Average one-way commute: 31.5 minutes for people who do not work from home.

Environment and hazard risk

Cook County, IL, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Very High

Top: cold wave

Storm events since 1996

2,829

Most often thunderstorm wind

Flood insurance policies

6,353

0.5% of homes, county

July high / Jan low

85° / 19°F

34.4 inches of rain a year

Hazards, floods and storm history Check a flood zone 430 historic places

Health statistics

Share of adults in Cook County, IL, CDC PLACES estimates

All 40 measures

Obesity

31.0%

U.S. 33.3% -2.3 pts

Diabetes

11.8%

U.S. 12.1% about the same

Smoking

11.1%

U.S. 12.8% -1.7 pts

Uninsured (18-64)

11.8%

U.S. 11.1% +0.7 pts

Cities, towns and ZIP codes in Cook County

Population shown

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Frequently asked questions

What is the largest city in Cook County, IL?: Chicago is the largest city or town in Cook County, with about 2,711,226 residents.
How many ZIP codes are in Cook County?: Cook County includes 166 ZIP Code Tabulation Areas, including 60004, 60005, 60007, 60008, 60016.
What is the population of Cook County, IL?: About 5,182,090 people live in Cook County, based on American Community Survey 5-year estimates.
What counties border Cook County?: Cook County borders DuPage County, Lake County, Will County, Kane County, Lake County, IN, McHenry County.