Resident Population in Miami County, OH was 110.87600 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Miami County, OH reached a record high of 110.87600 in January of 2023 and a record low of 84.34200 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Miami County, OH - last updated from the United States Federal Reserve on May of 2024.