Estimate, Median Age by Sex, Total Population (5-year estimate) in Clinton County, IL was 41.00000 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 Clinton County, IL reached a record high of 41.20000 in January of 2021 and a record low of 39.00000 in January of 2011. 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 Clinton County, IL - last updated from the United States Federal Reserve on May of 2024.