Rock Island Arsenal, Illinois Demographics & Population 2026

A note before these figures: with a population of 470, Rock Island Arsenal's ACS estimates come from a small number of survey responses and carry wide margins of error. Individual percentages below — particularly rates that round to 0% or 100% — are approximations, not precise measurements. See data.census.gov for the published margins of error.

Population Overview

Rock Island Arsenal is a small community located in Illinois, within Rock Island County. The total population is 470. It ranks as the 953rd most populous out of 1,445 Census-designated places in Illinois.

Age Demographics

The median age in Rock Island Arsenal is 39.3 years. This is about the same as the state median of 39.0 years. With 41.1% of the population under 18, Rock Island Arsenal has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The ACS records no residents below the poverty line in Rock Island Arsenal. In a community this small the estimate rests on very few survey responses, so it should be read as an absence of measurement rather than a measured absence of poverty. The unemployment rate is 19.1%. This is 227% higher than the state rate of 5.8%. Every occupied housing unit the survey reached in Rock Island Arsenal was renter-occupied. At this sample size that indicates no owner-occupied homes were captured rather than that none exist.

Race & Ethnicity

Rock Island Arsenal is a highly diverse community where no single racial or ethnic group constitutes a majority of the population. Hispanic or Latino residents account for 7.7%. The Black or African American population (0.6%) is well below the state average of 13.3%. The Hispanic or Latino population (7.7%) is well below the state average of 18.8%.

Education

23.8% of residents aged 25 and older hold a bachelor's degree or higher. This is 37% lower than the state rate of 37.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 89.5%.

Data Sources & Methodology

All demographic data for Rock Island Arsenal, Illinois is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against Illinois state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 1,445 Census-designated places in Illinois. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.