Rock City, Illinois Demographics & Population 2026

A note before these figures: with a population of 441, Rock City'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 City is a small community located in Illinois, within Stephenson County. The total population is 441. It ranks as the 974th most populous out of 1,445 Census-designated places in Illinois.

Age Demographics

The median age in Rock City is 26.8 years. This is 31% lower than the state median of 39.0 years. With 37.9% of the population under 18, Rock City has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The median household income in Rock City is $68,125. This is 18% lower than the state median of $83,390. It is also 16% lower than the national median of $80,734. The poverty rate stands at 4.5%. This is 62% lower than the state poverty rate of 11.8%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 3.9%. This is 34% lower than the state rate of 5.8%. The median home value is $122,700. Housing costs are 53% lower than the state median of $263,300. With a home-value-to-income ratio of just 1.8x, Rock City is one of the most affordable housing markets in the area. 79.9% of occupied housing units are owner-occupied. This homeownership rate is 19% higher than the state average of 67.1%.

Race & Ethnicity

The largest racial or ethnic group in Rock City is White (non-Hispanic), making up 64.2% of the population. Hispanic or Latino residents account for 33.1%. The Hispanic or Latino population is significantly higher than the state average (33.1% vs 18.8%).

Education

11.1% of residents aged 25 and older hold a bachelor's degree or higher. This is 71% 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 96.0%.

Data Sources & Methodology

All demographic data for Rock City, 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.