St. Charles County, Missouri Demographics 2026

Population Overview

St. Charles County is located in Missouri with a total population of 409,830. It is the 3rd most populous county out of 115 in Missouri.

Age Demographics

The median age in St. Charles County is 39.6 years. This is 2% higher than the state median of 38.9 years.

Economy, Income & Housing

The median household income in St. Charles County is $102,912. This is 49% higher than the state median of $68,920. Compared to the national median of $78,538, household income here is 31% higher. The poverty rate stands at 4.7%. This is 63% lower than the state poverty rate of 12.6%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 2.8%. This is 31% lower than the state rate of 4.1%. The median home value is $296,800. Housing costs are 38% higher than the state median of $215,600. With a home-value-to-income ratio of just 2.9x, St. Charles County is one of the most affordable housing markets in the area. 80.7% of occupied housing units are owner-occupied. This homeownership rate is 19% higher than the state average of 67.9%.

Race & Ethnicity

The largest racial or ethnic group in St. Charles County is White (non-Hispanic), making up 83.9% of the population. Black or African American residents account for 4.9%. The Black or African American population (4.9%) is well below the state average of 11.0%.

Education

42.4% of residents aged 25 and older hold a bachelor's degree or higher. This places St. Charles County in the top 10% of all cities in the state for educational attainment. This is 33% higher than the state rate of 31.9%. Nationally, 35.0% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 95.5%. Notably, 15.6% of adults hold a graduate or professional degree, indicating a highly educated workforce.