Washington County's 2026 population is estimated at 22,785, reflecting a 0.34% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Washington County is the 27th largest county in Iowa. The 2010 population was 21,687 and has grown 5.06% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.7 years
Female: 41 years
Male: 40.4 years
There are 17,028 adults, (4,538 of whom are seniors) in Washington County.
Female: 11,310 (50.1%)
Male: 11,251 (49.9%)
The racial composition of Washington County includes 90.14% White, 3.16% other race, and smaller percentages for Black or African American, Asian, Native Hawaiian or Pacific Islander, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 20,337 | 90.14% |
| Two or more races | 1,181 | 5.23% |
| Other race | 714 | 3.16% |
| Black or African American | 236 | 1.05% |
| Asian | 87 | 0.39% |
| Native Hawaiian or Pacific Islander | 4 | 0.02% |
| Native American | 2 | 0.01% |
Washington County 's average per capita income is $46,943. Household income levels show a median of $75,647. The poverty rate stands at 8.2%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $101,998 | - |
| Families | $88,958 | $110,017 |
| Households | $75,647 | $95,752 |
| Non Families | $40,704 | $59,196 |
Average Income
Median Household Income
Poverty Rate