Resident Population in Clinton County, OH was 41.93800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Clinton County, OH reached a record high of 43.06900 in January of 2008 and a record low of 31.46400 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Clinton County, OH - last updated from the United States Federal Reserve on May of 2024.