Rock Island County, Illinois
Located in Illinois, Rock Island County has a population of 142,757 residents and a median age of 40.3 years, making it the #474 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 15.5%. The median home value is $150,400, and the median household income is $67,159, which is 11% below the national median.
Demographics
Rock Island County has a population of 142,757, making it the #474 most populous county in the US. The median age is 40.3 years, which is 3.6% above the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in Rock Island County is $67,159, ranking #1,419 out of 3,222 counties — 10.6% below the national median. The poverty rate is 15.5% and unemployment stands at 5.6%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Rock Island County is $150,400 (-46.6% vs national). Renters pay a median of $889/mo and the homeownership rate is 69.7%.
Median Home Value Trend
Rankings →Household Type
Education
In Rock Island County, 24.7% of adults age 25+ hold a bachelor's degree or higher, which is 26.6% below the national average, ranking #1,265 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Rock Island County is 76.4 years. 16.5% of adults report poor or fair health and 7.4% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
14.1% of adults in Rock Island County smoke , 37.4% are obese , and 20.7% report excessive drinking. The drug overdose death rate is 15.1 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Rock Island County is 12.4 per 100,000 and the suicide rate is 16.0 per 100,000. Motor vehicle deaths occur at a rate of 9.0 per 100,000.
Homicide Rate Trend
Families & Children
21.0% of children in Rock Island County live in poverty and the infant mortality rate is 6.3 per 1,000 live births. The teen birth rate is 21.9 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Rock Island County is 63.4%. The mean commute time is 21.7 min, which is 21.4% below the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Rock Island County voted Democratic with a margin of 9.5%. The vote was 53.9% Dem / 44.4% Rep. Compared to 2020, the margin shifted 2.6 toward Republicans .
Vote Share Over Time
About Rock Island County, Illinois
Rock Island County, Illinois has a total population of 142,757, making it the 474th most populous county in the United States. The median age in Rock Island County is 40.3 years, which is 3.6% above the national median of 38.9 years.
The median household income in Rock Island County is $67,159, which ranks #1,419 of 3,222 counties nationwide. This is 10.6% below the national median of $75,149. The poverty rate is 15.5%, higher than the national rate of 12.6%. The unemployment rate stands at 5.6%.
The median home value in Rock Island County is $150,400, 46.6% below the national median. Renters in Rock Island County pay a median gross rent of $889 per month. The homeownership rate is 69.7%, compared to the national rate of 64.4%.
In Rock Island County, 24.7% of residents aged 25 and older hold a bachelor's degree or higher, 26.6% below the national average of 33.7%. Health insurance coverage stands at 93.9% of the population. The average commute time for workers is 21.7 min.
Rock Island County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 67.4% of the population, followed by Hispanic or Latino (14.2%) and Black (non-Hispanic) (10.9%).
All data for Rock Island County, Illinois comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.