Estimate, Median Age by Sex, Total Population (5-year estimate) in Gallatin County, IL was 46.90000 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 Gallatin County, IL reached a record high of 46.90000 in January of 2022 and a record low of 41.90000 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 Gallatin County, IL - last updated from the United States Federal Reserve on May of 2024.