Estimate, Median Age by Sex, Total Population (5-year estimate) in McLean County, IL was 34.00000 Years of Age in January of 2022, according to the United States Federal Reserve. Historically, Estimate, Median Age by Sex, Total Population (5-year estimate) in McLean County, IL reached a record high of 34.00000 in January of 2022 and a record low of 30.60000 in January of 2009. Trading Economics provides the current actual value, an historical data chart and related indicators for Estimate, Median Age by Sex, Total Population (5-year estimate) in McLean County, IL - last updated from the United States Federal Reserve on May of 2024.