Plymouth County, Iowa Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Plymouth County, IA Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
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B
Health Around averageHealthier than 87% of counties in Iowa
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B
Income Around averageAmong the top 5 wealthiest counties in Iowa
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D
Education Well below averageBetter educated than 73% of counties in Iowa
Source: Map AI Methodology
Population: density and quick facts
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| Population | 25,747 | 3,204,793 | 337,468,954 |
| Population density (per sq mi) | 29.8 | 57.0 | 86.4 |
| Population growth (%/yr) | 0.38% | 0.41% | 0.59% |
| Median age | 41.6 | 36.8 | 37.3 |
| Households | 10,313 | 1,308,457 | 130,235,071 |
Population in Plymouth County grew by 5.7% from 2009 to 2024, reaching 25,747 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Plymouth County is Gen X, aged 45–60, at 20.5% of residents. That is 1.7 points above Iowa as a whole.
- Gen Z 13–28 4,889 19.0% -3.3 pts
- Millennials 29–44 4,953 19.2% -1.2 pts
- Gen X 45–60 5,290 20.5% +1.7 pts
- Boomers 61–79 4,733 18.4% +0.7 pts
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below Iowa, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 49.4% of the people living in Plymouth County and men 50.6%.
- Women 49.4% Iowa 50.0%
- Men 50.6% Iowa 50.0%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Plymouth County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Plymouth County has a the economy index of B, which means it is quite prosperous.
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| Median household income | $83,321 | $75,133 | $80,455 |
| Income growth (%/yr) | 4.11% | 3.99% | 4.80% |
| Unemployment rate | 2.2% | 3.6% | 5.2% |
The median household income in Plymouth County is about 11% higher than in Iowa.
Housing
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| Median home price | $28,068 | $153,425 | $248,835 |
| Median rent | $910 | $971 | $1,407 |
| Homeownership rate | 73.6% | 71.7% | 65.2% |
The median home price in Plymouth County is about 2.6 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $910 per month for that long.
Commute Time & Mobility
Commuters in Plymouth County spend about 32 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 133 hours, about 5.6 full days, spent commuting.
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 16.0 | 17.0 | 22.4 |
| Round-trip commute (min) | 32.0 | 33.9 | 44.8 |
| Yearly time spent (hours) | 133 | 141 | 187 |
| Estimated yearly cost | $4,132 | $4,382 | $5,790 |
| Work from home | 9.2% | 11.3% | 15.0% |
| Highway traffic (vehicles/day) | 4,073 | 4,993 | 8,813 |
| Local road traffic (vehicles/day) | 596 | 606 | 1,355 |
Fastest commutes among counties in
Iowa:
Sioux County (10.1 min), Union County (10.4 min), Cass County (10.6 min).
Slowest:
Monroe County (30.4 min), Madison County (30.1 min), Mills County (26.7 min).
The average commute time in Plymouth County is 16 minutes, shorter than the 17 minutes in Iowa.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
Plymouth County has a education index of D, which means it is barely educated.
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 22.7% | 27.9% | 31.6% |
| Average household size | 2.46 | 2.37 | 2.53 |
Highest education index among counties in
Iowa:
Johnson County (0.4), Dallas County (0.4), Story County (0.4).
Lowest:
Crawford County (0.2), Wayne County (0.2), Louisa County (0.2).
Health
Plymouth County has a health index of B, which means it is quite healthy.
| Metric | Plymouth County | Iowa Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 80.8 | 79.2 | 78.3 |
| Self-rated poor health | 12.4% | 13.6% | 16.3% |
| Smokers | 16.9% | 17.6% | 19.0% |
Highest health index among counties in
Iowa:
Johnson County (0.8), Story County (0.8), Winneshiek County (0.8).
Lowest:
Davis County (0.8), Wayne County (0.8), Appanoose County (0.8).
Plymouth County, IA Compared With Nearby Counties
Plymouth County, IA is the 3rd largest of the 4 counties compared here, 25,747 residents against a local median of 36,212. The measure that sets Plymouth County, IA apart most is median home price: $28,068, 104% above the local median of $13,749.
Commute tells the same story from another angle: 16.0 min against a local median of 13.1 min, 22% above it. The one measure here that carries a verdict is commute, and at 22% above the local median it puts Plymouth County, IA at the weaker end of the local range. The counties themselves spread $86,526 on median home price, so Plymouth County, IA sits at one end of an already wide local range rather than apart from it. Plymouth County, IA has the 2nd highest median home price of the 4 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Plymouth County, IA | 25,747 | $83,321 #2/4 | $28,068 #2/4 | 16.0 min #3/4 |
| Sioux County, IA | 36,212 | $88,224 | $13,749 | 10.1 min |
| Woodbury County, IA | 106,250 | $73,309 | $94,303 | 16.4 min |
| Dakota County, NE | 21,354 | $70,667 | $7,777 | 13.1 min |
Frequently Asked Questions
Common questions about Plymouth County, Iowa.
How big is Plymouth County, Iowa by population?
About 25,747 people live in Plymouth County, Iowa, in 10,313 households of 2.5 people on average. The median age is 41.6, so residents are older than the U.S. median of 37.3 by about 4 years.
Is Plymouth County, Iowa urban or rural?
Averaged over its land area, Plymouth County, Iowa has 30 people per square mile, a density typical of rural areas. That is about 34% of the U.S. average of 86.
Can a typical household afford a home in Plymouth County, Iowa?
The median home costs 0.3 times the median household income ($28,068 against $83,321), compared with 3.1 times nationally. That is within the traditional rule of thumb of about 3 times income. Median rent of $910 a month takes about 13% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
Is unemployment high in Plymouth County, Iowa?
Unemployment in Plymouth County, Iowa is only 2.2%, well below the U.S. rate of 5.2%, a sign of a tight labor market where employers compete for workers.
How common is a college degree in Plymouth County, Iowa?
22.7% of adults in Plymouth County, Iowa hold a bachelor's degree or higher (about 1 in 4), well below the U.S. share of 31.6%.
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