Resident Population in Allen County, KS was 12.41200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Allen County, KS reached a record high of 15.86500 in January of 1984 and a record low of 12.40400 in January of 2019. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Allen County, KS - last updated from the United States Federal Reserve on May of 2024.