Johnson County, Iowa Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 4th-largest in Iowa
The population of Johnson County, Iowa is 154,881 as of the 2023 American Community Survey, making it the 4th-largest county in Iowa. The median household income is $74,721, the median home value is $293,100, and the median age is 30.8.
The population of Johnson County has grown 21.9% since 2010 (131,344 → 160,080), a +1.42% annualized rate.
154,881
Population
+1.42%
Annual growth
253
People / sq mi
$74,721
Median Income
$293,100
Median Home Value
Johnson County covers 613 sq mi of land at 252.7 people per square mile.
About Johnson County, IA
Educational attainment is the headline number in Johnson County: 54.6% of adults 25 and older have a four-year degree. Johnson County is a county in Iowa with a population of 154,881. It is the #4-largest of all counties in Iowa nationally.
Households take in a median $74,721, comfortably near the US median of $78,538. The poverty rate, 6.1%, is on the lower side for US counties and below the national 12.4%. Home values run above average at $293,100, with typical rent around $1,104.
Degree attainment is near the top of the range for US counties: 54.6% of adults 25+ hold a bachelor’s, above the 35.0% national rate. Remote work is on the higher side at 12.6%, below the national 14.0%, and the average commute runs about 20 minutes each way.
The education numbers are the throughline: a college-heavy population in Johnson County usually coincides with higher incomes and a workforce concentrated in professional and information industries.
Johnson County Population History (2010-2024)
The county of Johnson County had a population of 131,344 in 2010 and 160,080 in 2024, a 21.9% growth over 14 years. The peak was 160,080 in 2024. Average annual growth rate: 1.42%.
160,080
Population (2024)
131,344
Population (2010)
160,080
Peak (2024)
1.42%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 131,344 |
| 2011 | 134,125 |
| 2012 | 137,180 |
| 2013 | 140,266 |
| 2014 | 142,874 |
| 2015 | 145,114 |
| 2016 | 147,167 |
| 2017 | 149,703 |
| 2018 | 151,003 |
| 2019 | 152,480 |
| 2020 | 153,052 |
| 2021 | 155,047 |
| 2022 | 156,815 |
| 2023 | 158,202 |
| 2024 | 160,080 |
Race & Ethnicity
| White | 77.6% |
| Black or African American | 7.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.3% |
| Two or More Races | 0.0% |
Age & Sex
30.8
Median Age
50.3%
Female
49.7%
Male
12.9%
Age 65+
Age Distribution
Children (under 15): 16.3% · Seniors (65+): 12.9%
Income & Poverty
| Median household income | $74,721+$1,574 vs state |
| Mean household income | $108,967 |
| Per-capita income | $44,699 |
| Poverty rate | 6.1%-0.8% vs state |
| Unemployment rate | 2.5% |
| Employment-to-population | 67.1% |
Top Industries by Employment
The largest employment sector in Johnson County is professional & business services, accounting for 40.7% of workers.
How residents commute
4.1%
Drive alone
7.9%
Carpool
64.9%
Public transit
12.6%
Work from home
19.7 min
Avg commute
Housing
$293,100+$97,200 vs state
Median home value
$1,104
Median rent
58.8%
Homeownership rate
67,211
Total housing units
92.6%
Occupied
7.4%
Vacant
41.2%
Renter-occupied
Social & access
94.9%
With health insurance
96.6%
With broadband internet
31.3%
Foreign-born
3.9%
Veterans (18+)
9.5%
With a disability
84.5%
Speak language other than English at home
Education
96.2%
High School+
54.6%
Bachelor's+
Largest cities in Iowa
Other counties in Iowa
Part of Iowa
Metro areas in Iowa
County rankings
Frequently Asked Questions
Johnson County, Iowa has a population of 154,881 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 4th-largest county in Iowa. Population density is 253 people per square mile.
The population of Johnson County has grown 21.9% since 2010 (131,344 → 160,080), a +1.42% annualized rate.
The median household income in Johnson County, Iowa is $74,721, with mean (average) household income of $108,967 and per-capita income of $44,699. 6.1% of residents live below the federal poverty level.
In Johnson County, the largest racial and ethnic groups are White (77.6%), Black or African American (7.6%), Hispanic or Latino (1.3%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Johnson County, Iowa is 30.8 years. Residents are 50.3% female and 49.7% male.
The median home value in Johnson County is $293,100 and median monthly rent is $1,104. 58.8% of occupied housing units are owner-occupied. The county has 67,211 total housing units, 7.4% of which are vacant.
The largest employment sector in Johnson County, Iowa is professional, scientific, and management services, employing 40.7% of workers. The unemployment rate is 2.5%.
Des Moines is among the largest cities associated with Johnson County, Iowa, with a population of 212,464.
Johnson County, IA Climate
Johnson County, IA has an average annual temperature of 9.7°C (49°F) and receives about 909 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
9.7°C
Avg Temp
909
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -7° / 20° | 28 mm |
| February | -3° / 26° | 26 mm |
| March | 3° / 38° | 58 mm |
| April | 10° / 50° | 88 mm |
| May | 16° / 62° | 104 mm |
| June | 22° / 71° | 116 mm |
| July | 24° / 75° | 114 mm |
| August | 23° / 73° | 109 mm |
| September | 18° / 64° | 102 mm |
| October | 12° / 53° | 69 mm |
| November | 3° / 38° | 55 mm |
| December | -4° / 25° | 40 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Johnson County, IA
The most comfortable months to visit Johnson County, IA are typically June, August and September, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 30°C high). The coldest is January (near -12°C low). June is usually the wettest month.
Where to stay near Johnson County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.