Resident Population in Ontonagon County, MI was 5.90600 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Ontonagon County, MI reached a record high of 11.40000 in January of 1975 and a record low of 5.71300 in January of 2019. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Ontonagon County, MI - last updated from the United States Federal Reserve on May of 2024.