Plymouth County's 2026 population is estimated at 25,945, reflecting a 0.23% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Plymouth County is the 24th largest county in Iowa. The 2010 population was 24,978 and has grown 3.87% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.3 years
Female: 41.9 years
Male: 40.3 years
There are 19,304 adults, (5,096 of whom are seniors) in Plymouth County.
Female: 12,632 (49.1%)
Male: 13,115 (50.9%)
The racial composition of Plymouth County includes 89.42% White, and smaller percentages for Black or African American, other race, Asian, Native Hawaiian or Pacific Islander, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 23,022 | 89.42% |
| Two or more races | 1,222 | 4.75% |
| Black or African American | 615 | 2.39% |
| Other race | 531 | 2.06% |
| Asian | 135 | 0.52% |
| Native Hawaiian or Pacific Islander | 112 | 0.44% |
| Native American | 110 | 0.43% |
Plymouth County 's average per capita income is $51,815. Household income levels show a median of $83,251. The poverty rate stands at 6.9%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $111,690 | - |
| Families | $97,910 | $117,624 |
| Households | $83,251 | $101,116 |
| Non Families | $46,225 | $59,163 |
Average Income
Median Household Income
Poverty Rate
