Johnson County, Illinois Demographics 2026

Population Overview

Johnson County is located in Illinois with a total population of 13,350. It is the 79th most populous county out of 102 in Illinois.

Age Demographics

The median age in Johnson County is 42.7 years. This is 10% higher than the state median of 38.9 years.

Economy, Income & Housing

The median household income in Johnson County is $65,203. This is 20% lower than the state median of $81,702. Compared to the national median of $78,538, household income here is 17% lower. The poverty rate stands at 16.7%. This is 42% higher than the state poverty rate of 11.7%. The unemployment rate is 2.5%. This is 58% lower than the state rate of 5.8%. The median home value is $148,200. Housing costs are 41% lower than the state median of $250,500. With a home-value-to-income ratio of just 2.3x, Johnson County is one of the most affordable housing markets in the area. 84.7% of occupied housing units are owner-occupied. This homeownership rate is 27% higher than the state average of 66.8%.

Race & Ethnicity

The largest racial or ethnic group in Johnson County is White (non-Hispanic), making up 81.0% of the population. Black or African American residents account for 7.5%. The Hispanic or Latino population (4.3%) is well below the state average of 18.5%. The Asian population (0.3%) is well below the state average of 5.8%.

Education

18.8% of residents aged 25 and older hold a bachelor's degree or higher. This is 49% lower than the state rate of 37.2%. Nationally, 35.0% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 85.9%.