
Henry County is a county in the U.S. state of Ohio. As of the 2020 census, the population was 27,662. Its county seat is Napoleon. The county was created in 1820. It is named for Patrick Henry.
According to the U.S. Census Bureau, the county has a total area of 420 square miles (1,100 km2), of which 416 square miles (1,080 km2) is land and 3.7 square miles (9.6 km2) (0.9%) is water.