Resident Population in Allen County, IN was 394.54500 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Allen County, IN reached a record high of 394.54500 in January of 2023 and a record low of 280.45500 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Allen County, IN - last updated from the United States Federal Reserve on May of 2024.