What is the largest city in Johnson County, IA?

Iowa City is the largest city or town in Johnson County, with about 75,752 residents.

How many ZIP codes are in Johnson County?

Johnson County includes 12 ZIP Code Tabulation Areas, including 52235, 52240, 52241, 52242, 52245.

What is the population of Johnson County, IA?

About 156,639 people live in Johnson County, based on American Community Survey 5-year estimates.

What counties border Johnson County?

Johnson County borders Linn County, Muscatine County, Benton County, Washington County, Cedar County, Iowa County, Louisa County.

Johnson County, IA: Cities, ZIP Codes & Local Data

Population

156,639

Land area

613sq mi

People per sq mi

256

ZIP codes

12

Johnson County at a glance

Johnson County is about 4.4 times as dense as Iowa as a whole.
By population, it ranks 4th among 99 counties in Iowa.
The median household income is $74,935, close to the Iowa median.
A typical owner-occupied home is valued at $308,600 (48% above Iowa) and median rent is $1,122 a month.
Its largest cities are Iowa City (75,752), Coralville (23,234) and North Liberty (21,125).

Local data for Johnson County, IA

Counts from official public data

Housing and community stats

Johnson County, IA, American Community Survey 2020-2024

Full profile

Median household income

$74,935

Poverty rate

17.1%

Median home value

$308,600

Prices +4.5% in a year

Median rent

$1,122/mo

Homeownership

59.4%

Bachelor's or higher

55.2%

Median age

31.0

Average commute

19.4 min

Largest reported origins and ancestries: German Americans (43,919), Irish Americans (22,790), Mexican Americans (6,166).

Home values and rents Income, education and commute

Economy and federal money

Jobs, income, federal spending and pandemic loans

Details

Unemployment rate

2.8%

Sep 2026, +0.3 pts in a year

Average annual pay

$66,505

85,623 jobs, 2025

Income per person

$66,028

BEA, 2024

Federal spending

$1.1B

FY 2026, $7,013 per person

PPP loans

$290M

4,775 loans, 36,753 jobs reported

Campaign donations

$2.6M

Itemized, 2026 cycle

Economy Federal spending PPP loans

How people get to work

Johnson County, IA, workers 16 and older. American Community Survey 5-year estimates

Drove alone65.2%
Carpooled6.3%
Public transit3.7%
Walked8.2%
Bicycle1.7%
Taxi, ride-hailing, motorcycle or other1.3%
Worked from home13.7%

Average one-way commute: 19.4 minutes for people who do not work from home.

Environment and hazard risk

Johnson County, IA, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Relatively Moderate

Top: strong wind

Storm events since 1996

801

Most often thunderstorm wind

Flood insurance policies

360

0.7% of homes, county

July high / Jan low

86° / 15°F

35.7 inches of rain a year

Hazards, floods and storm history Check a flood zone 71 historic places

Health statistics

Share of adults in Johnson County, IA, CDC PLACES estimates

All 40 measures

Obesity

30.4%

U.S. 33.3% -2.9 pts

Diabetes

8.8%

U.S. 12.1% -3.3 pts

Smoking

10.9%

U.S. 12.8% -1.9 pts

Uninsured (18-64)

6.3%

U.S. 11.1% -4.8 pts

Cities, towns and ZIP codes in Johnson County

Population shown

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Frequently asked questions

What is the largest city in Johnson County, IA?: Iowa City is the largest city or town in Johnson County, with about 75,752 residents.
How many ZIP codes are in Johnson County?: Johnson County includes 12 ZIP Code Tabulation Areas, including 52235, 52240, 52241, 52242, 52245.
What is the population of Johnson County, IA?: About 156,639 people live in Johnson County, based on American Community Survey 5-year estimates.
What counties border Johnson County?: Johnson County borders Linn County, Muscatine County, Benton County, Washington County, Cedar County, Iowa County, Louisa County.