Madison County, Illinois Demographics 2026

Population Overview

Madison County is located in Illinois with a total population of 264,238. It is the 8th most populous county out of 102 in Illinois. The county encompasses 34 Census-designated places.

Age Demographics

The median age in Madison County is 40.2 years. This is 3% higher than the state median of 39.0 years.

Economy, Income & Housing

The median household income in Madison County is $75,793. This is 9% lower than the state median of $83,390. It is also 6% lower than the national median of $80,734. The poverty rate stands at 11.1%. This is 6% lower than the state poverty rate of 11.8%. The unemployment rate is 4.6%. This is 21% lower than the state rate of 5.8%. The median home value is $173,000. Housing costs are 34% lower than the state median of $263,300. With a home-value-to-income ratio of just 2.3x, Madison County is one of the most affordable housing markets in the area. 74.2% of occupied housing units are owner-occupied. This homeownership rate is 11% higher than the state average of 67.1%.

Race & Ethnicity

The largest racial or ethnic group in Madison County is White (non-Hispanic), making up 81.8% of the population. Black or African American residents account for 7.7%. The Hispanic or Latino population (4.3%) is well below the state average of 18.8%. The Asian population (0.9%) is well below the state average of 5.9%.

Education

31.0% of residents aged 25 and older hold a bachelor's degree or higher. This is 18% 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 93.9%.

Data Sources & Methodology

All figures for Madison 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.