Estimate, Median Age by Sex, Total Population (5-year estimate) in Sullivan County, IN was 40.90000 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 Sullivan County, IN reached a record high of 41.40000 in January of 2017 and a record low of 37.80000 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 Sullivan County, IN - last updated from the United States Federal Reserve on May of 2024.