Hamilton County, Illinois Demographics 2026

Population Overview

Hamilton County is located in Illinois with a total population of 7,916. It is the 89th most populous county out of 102 in Illinois. The county encompasses 4 Census-designated places.

Age Demographics

The median age in Hamilton County is 43.9 years. This is 13% higher than the state median of 39.0 years. 10.5% of residents are 75 or older, suggesting a significant retirement-age population with implications for healthcare services and senior housing.

Economy, Income & Housing

The median household income in Hamilton County is $65,746. This is 21% lower than the state median of $83,390. It is also 19% lower than the national median of $80,734. The poverty rate stands at 12.1%. This is 2% higher than the state poverty rate of 11.8%. The unemployment rate is 5.1%. This is 12% lower than the state rate of 5.8%. The median home value is $113,700. Housing costs are 57% lower than the state median of $263,300. With a home-value-to-income ratio of just 1.7x, Hamilton County is one of the most affordable housing markets in the area. 76.4% of occupied housing units are owner-occupied. This homeownership rate is 14% higher than the state average of 67.1%.

Race & Ethnicity

Hamilton County has a predominantly White (non-Hispanic) population, comprising 94.7% of all residents. Hispanic or Latino residents account for 0.7%. The White (non-Hispanic) population is significantly higher than the state average (94.7% vs 58.1%). The Black or African American population (0.2%) is well below the state average of 13.3%. The Hispanic or Latino population (0.7%) is well below the state average of 18.8%. The Asian population (0.5%) is well below the state average of 5.9%.

Education

21.0% of residents aged 25 and older hold a bachelor's degree or higher. This is 44% 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 91.6%.

Data Sources & Methodology

All figures for Hamilton County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against Illinois and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.