Resident Population in Madison County, OH was 45.53100 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Madison County, OH reached a record high of 45.53100 in January of 2024 and a record low of 28.30000 in January of 1973. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Madison County, OH - last updated from the United States Federal Reserve on April of 2026.