Jefferson County's 2026 population is estimated at 580,213, reflecting a 0.14% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Jefferson County is the 4th largest county in Colorado. The 2010 population was 535,567 and has grown 8.34% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.5 years
Female: 41.6 years
Male: 39.4 years
There are 472,407 adults, (103,643 of whom are seniors) in Jefferson County.
Female: 287,789 (49.7%)
Male: 291,588 (50.3%)
The racial composition of Jefferson County includes 79.47% White, and smaller percentages for other race, Asian, Black or African American, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 460,410 | 79.47% |
| Two or more races | 73,436 | 12.67% |
| Other race | 17,022 | 2.94% |
| Asian | 16,970 | 2.93% |
| Black or African American | 6,880 | 1.19% |
| Native American | 4,226 | 0.73% |
| Native Hawaiian or Pacific Islander | 433 | 0.07% |
Jefferson County 's average per capita income is $68,137. Household income levels show a median of $110,656. The poverty rate stands at 6.68%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $155,137 | $189,722 |
| Families | $138,654 | $172,185 |
| Households | $110,656 | $142,995 |
| Non Families | $68,952 | $89,701 |
Average Income
Median Household Income
Poverty Rate
