McHenry County, Illinois Demographics 2026

Population Overview

McHenry County is located in Illinois with a total population of 311,366. It is the 6th most populous county out of 102 in Illinois.

Age Demographics

The median age in McHenry County is 40.4 years. This is 4% higher than the state median of 38.9 years.

Economy, Income & Housing

The median household income in McHenry County is $102,836. This is 26% higher than the state median of $81,702. Compared to the national median of $78,538, household income here is 31% higher. The poverty rate stands at 6.1%. This is 48% lower 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 $286,900. Housing costs are 15% higher than the state median of $250,500. With a home-value-to-income ratio of just 2.8x, McHenry County is one of the most affordable housing markets in the area. 82.6% of occupied housing units are owner-occupied. This homeownership rate is 24% higher than the state average of 66.8%.

Race & Ethnicity

The largest racial or ethnic group in McHenry County is White (non-Hispanic), making up 76.9% of the population. Hispanic or Latino residents account for 15.6%. The Black or African American population (1.5%) is well below the state average of 13.6%. The Asian population (2.8%) is well below the state average of 5.8%.

Education

35.2% of residents aged 25 and older hold a bachelor's degree or higher. This is 5% 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 93.7%.