Rock Island County's 2026 population is estimated at 144,315, reflecting a 0.55% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Rock Island County is the 15th largest county in Illinois. The 2010 population was 147,613 and has grown -2.23% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.3 years
Female: 41.3 years
Male: 39 years
There are 110,666 adults, (29,061 of whom are seniors) in Rock Island County.
Female: 72,135 (50.5%)
Male: 70,622 (49.5%)
The racial composition of Rock Island County includes 71.5% White, 11.4% Black or African American, 4.37% other race, and smaller percentages for Asian, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 102,074 | 71.5% |
| Black or African American | 16,270 | 11.4% |
| Two or more races | 13,440 | 9.41% |
| Other race | 6,244 | 4.37% |
| Asian | 3,943 | 2.76% |
| Native American | 555 | 0.39% |
| Native Hawaiian or Pacific Islander | 231 | 0.16% |
Rock Island County 's average per capita income is $47,164. Household income levels show a median of $67,159. The poverty rate stands at 15.5%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $105,313 | $122,819 |
| Families | $87,978 | $103,596 |
| Households | $67,159 | $85,299 |
| Non Families | $40,667 | $54,673 |
Average Income
Median Household Income
Poverty Rate