Rock Island County Flag

Rock Island County

State:
Illinois
County Seat:
Rock Island

Rock Island County's estimated 2026 population is 142,147 with a growth rate of 0.2% in the past year according to the most recent United States census data. Rock Island County is the 15th largest county in Illinois. The 2010 population was 147,613 and has seen a growth of -3.7% since that time.

142,147
Total Population
333
Population Density (mi²)
15
Population Rank (State)
278 0.2%
Annual Population Growth

Rock Island County Population

Demographics

Economics and Income Statistics