Rock County's 2026 population is estimated at 167,497, reflecting a 0.61% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Rock County is the 9th largest county in Wisconsin. The 2010 population was 160,261 and has grown 4.52% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.3 years
Female: 41.4 years
Male: 39.1 years
There are 127,547 adults, (29,268 of whom are seniors) in Rock County.
Female: 82,546 (50.2%)
Male: 81,804 (49.8%)
The racial composition of Rock County includes 81.63% White, 4.7% Black or African American, and smaller percentages for other race, Asian, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 134,161 | 81.63% |
| Two or more races | 15,328 | 9.33% |
| Black or African American | 7,727 | 4.7% |
| Other race | 4,782 | 2.91% |
| Asian | 1,779 | 1.08% |
| Native American | 564 | 0.34% |
| Native Hawaiian or Pacific Islander | 9 | 0.01% |
Rock County 's average per capita income is $50,055. Household income levels show a median of $75,673. The poverty rate stands at 9.26%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $104,227 | $121,135 |
| Families | $90,467 | $106,271 |
| Households | $75,673 | $91,984 |
| Non Families | $45,841 | $61,565 |
Average Income
Median Household Income
Poverty Rate