Jefferson County's 2026 population is estimated at 15,177, reflecting a -0.75% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Jefferson County is the 48th largest county in Iowa. The 2010 population was 16,835 and has grown -9.85% since 2010.
Overall: 43.7 years
Female: 47.3 years
Male: 41.1 years
There are 13,013 adults, (4,192 of whom are seniors) in Jefferson County.
Female: 7,621 (48.5%)
Male: 8,084 (51.5%)
The racial composition of Jefferson County includes 84.39% White, 8.18% Asian, and smaller percentages for Black or African American, Native American, other race and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 13,253 | 84.39% |
| Asian | 1,285 | 8.18% |
| Two or more races | 543 | 3.46% |
| Black or African American | 399 | 2.54% |
| Native American | 123 | 0.78% |
| Other race | 102 | 0.65% |
Jefferson County 's average per capita income is $36,813. Household income levels show a median of $61,620. The poverty rate stands at 15.19%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $101,443 | - |
| Families | $95,344 | $110,219 |
| Households | $61,620 | $82,383 |
| Non Families | $33,868 | $48,523 |
Average Income
Median Household Income
Poverty Rate
