Resident Population in Decatur County, KS was 2.71200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Decatur County, KS reached a record high of 4.98800 in January of 1970 and a record low of 2.68900 in January of 2022. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Decatur County, KS - last updated from the United States Federal Reserve on May of 2024.