Mercer County, Illinois Demographics 2026

Population Overview

Mercer County is located in Illinois with a total population of 15,619. It is the 69th most populous county out of 102 in Illinois.

Age Demographics

The median age in Mercer County is 44.5 years. This is 14% higher than the state median of 38.9 years.

Economy, Income & Housing

The median household income in Mercer County is $71,710. This is 12% lower than the state median of $81,702. Compared to the national median of $78,538, household income here is 9% lower. The poverty rate stands at 7.9%. This is 33% lower than the state poverty rate of 11.7%. The unemployment rate is 3.0%. This is 47% lower than the state rate of 5.8%. The median home value is $139,300. Housing costs are 44% lower than the state median of $250,500. With a home-value-to-income ratio of just 1.9x, Mercer County is one of the most affordable housing markets in the area. 82.7% of occupied housing units are owner-occupied. This homeownership rate is 24% higher than the state average of 66.8%.

Race & Ethnicity

Mercer County has a predominantly White (non-Hispanic) population, comprising 93.5% of all residents. Hispanic or Latino residents account for 3.3%. The White (non-Hispanic) population is significantly higher than the state average (93.5% vs 58.8%). The Black or African American population (0.6%) is well below the state average of 13.6%. The Hispanic or Latino population (3.3%) is well below the state average of 18.5%. The Asian population (0.3%) is well below the state average of 5.8%.

Education

18.9% 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 93.3%.