Stephenson County, Illinois Demographics 2026

Population Overview

Stephenson County is located in Illinois with a total population of 44,042. It is the 33rd most populous county out of 102 in Illinois.

Age Demographics

The median age in Stephenson County is 45.2 years. This is 16% higher than the state median of 38.9 years. 10.2% 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 Stephenson County is $61,943. This is 24% lower than the state median of $81,702. Compared to the national median of $78,538, household income here is 21% lower. The poverty rate stands at 13.1%. This is 12% higher than the state poverty rate of 11.7%. The unemployment rate is 4.7%. This is 19% lower than the state rate of 5.8%. The median home value is $127,500. Housing costs are 49% lower than the state median of $250,500. With a home-value-to-income ratio of just 2.1x, Stephenson County is one of the most affordable housing markets in the area. 71.0% of occupied housing units are owner-occupied. This homeownership rate is 6% higher than the state average of 66.8%.

Race & Ethnicity

The largest racial or ethnic group in Stephenson County is White (non-Hispanic), making up 80.0% of the population. Black or African American residents account for 8.4%. The Hispanic or Latino population (5.3%) is well below the state average of 18.5%. The Asian population (0.8%) is well below the state average of 5.8%.

Education

21.7% of residents aged 25 and older hold a bachelor's degree or higher. This is 42% 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 91.5%.