Plymouth County, Iowa Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 24th-largest in Iowa
The population of Plymouth County, Iowa is 25,699 as of the 2023 American Community Survey, making it the 24th-largest county in Iowa. The median household income is $81,600, the median home value is $218,600, and the median age is 41.1.
The population of Plymouth County has grown 3.4% since 2010 (24,978 → 25,825), a +0.24% annualized rate.
25,699
Population
+0.24%
Annual growth
30
People / sq mi
$81,600
Median Income
$218,600
Median Home Value
Plymouth County covers 863 sq mi of land at 29.8 people per square mile.
About Plymouth County, IA
Plymouth County is a county in Iowa with a population of 25,699. It ranks #24 among counties in Iowa by population. The median age is 41.1, older than the national median. The population is 50.9% male and 49.1% female.
The median household income in Plymouth County is $81,600, above the US median of $74,580. 4.1% of residents live below the federal poverty level. Home values sit at a median of $218,600, with monthly rent averaging $865. The homeownership rate of 73.7% is higher than the national rate of 64.8%.
Educational attainment in Plymouth County reflects 23.9% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 8.6% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 18.8 minutes each way.
Plymouth County Population History (2010-2024)
The county of Plymouth County had a population of 24,978 in 2010 and 25,825 in 2024, a 3.4% growth over 14 years. The peak was 25,825 in 2024. Average annual growth rate: 0.24%.
25,825
Population (2024)
24,978
Population (2010)
25,825
Peak (2024)
0.24%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 24,978 |
| 2011 | 24,824 |
| 2012 | 24,836 |
| 2013 | 24,937 |
| 2014 | 24,918 |
| 2015 | 24,912 |
| 2016 | 25,207 |
| 2017 | 25,053 |
| 2018 | 25,024 |
| 2019 | 25,200 |
| 2020 | 25,694 |
| 2021 | 25,738 |
| 2022 | 25,714 |
| 2023 | 25,765 |
| 2024 | 25,825 |
Race & Ethnicity
| White | 90.5% |
| Black or African American | 2.4% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.0% |
| Two or More Races | 0.0% |
Age & Sex
41.1
Median Age
49.1%
Female
50.9%
Male
19.3%
Age 65+
Age Distribution
Children (under 15): 20.1% · Seniors (65+): 19.3%
Income & Poverty
| Median household income | $81,600+$8,453 vs state |
| Mean household income | $103,320 |
| Per-capita income | $42,241 |
| Poverty rate | 4.1%-2.8% vs state |
| Unemployment rate | 1.3% |
| Employment-to-population | 67.2% |
Top Industries by Employment
The largest employment sector in Plymouth County is professional & business services, accounting for 22.3% of workers.
How residents commute
0.4%
Drive alone
2.2%
Carpool
79.3%
Public transit
8.6%
Work from home
18.8 min
Avg commute
Housing
$218,600+$22,700 vs state
Median home value
$865
Median rent
73.7%
Homeownership rate
10,863
Total housing units
94.8%
Occupied
5.2%
Vacant
26.3%
Renter-occupied
Social & access
94.4%
With health insurance
93.7%
With broadband internet
18.8%
Foreign-born
7.8%
Veterans (18+)
11.8%
With a disability
92.4%
Speak language other than English at home
Education
94.2%
High School+
23.9%
Bachelor's+
Largest cities in Iowa
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Part of Iowa
Metro areas in Iowa
County rankings
Frequently Asked Questions
Plymouth County, Iowa has a population of 25,699 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 24th-largest county in Iowa. Population density is 30 people per square mile.
The population of Plymouth County has grown 3.4% since 2010 (24,978 → 25,825), a +0.24% annualized rate.
The median household income in Plymouth County, Iowa is $81,600, with mean (average) household income of $103,320 and per-capita income of $42,241. 4.1% of residents live below the federal poverty level.
In Plymouth County, the largest racial and ethnic groups are White (90.5%), Black or African American (2.4%), Hispanic or Latino (1.0%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Plymouth County, Iowa is 41.1 years. Residents are 49.1% female and 50.9% male.
The median home value in Plymouth County is $218,600 and median monthly rent is $865. 73.7% of occupied housing units are owner-occupied. The county has 10,863 total housing units, 5.2% of which are vacant.
The largest employment sector in Plymouth County, Iowa is professional, scientific, and management services, employing 22.3% of workers. The unemployment rate is 1.3%.
Des Moines is among the largest cities associated with Plymouth County, Iowa, with a population of 212,464.
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Statewide data for Iowa
Population, race, income, age, and trends across Iowa
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.