Resident Population in Ionia County, MI was 66.26200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Ionia County, MI reached a record high of 66.85500 in January of 2020 and a record low of 45.84800 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Ionia County, MI - last updated from the United States Federal Reserve on May of 2024.