Marion County's 2026 population is estimated at 34,708, reflecting a 0.96% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Marion County is the 21st largest county in Iowa. The 2010 population was 33,225 and has grown 4.46% since 2010.
Data after 2023 is projected based on recent change
Overall: 39.9 years
Female: 41 years
Male: 38.6 years
There are 25,873 adults, (6,515 of whom are seniors) in Marion County.
Female: 16,759 (49.8%)
Male: 16,883 (50.2%)
The racial composition of Marion County includes 94.41% White, and smaller percentages for Asian, other race, Black or African American, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 31,760 | 94.41% |
| Two or more races | 1,039 | 3.09% |
| Asian | 473 | 1.41% |
| Other race | 217 | 0.65% |
| Black or African American | 141 | 0.42% |
| Native American | 12 | 0.04% |
Marion County 's average per capita income is $51,856. Household income levels show a median of $78,680. The poverty rate stands at 8.17%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $106,226 | - |
| Families | $99,269 | $118,610 |
| Households | $78,680 | $100,547 |
| Non Families | $43,168 | $59,770 |
Average Income
Median Household Income
Poverty Rate
