Sponsored Topics. Germantown is a village in Montgomery County, Ohio, United States. The population was 4,884 at the 2000 census. It is part of the Dayton Metropolitan Statistical Area. Germantown is located at 39°37′38″N 84°21′57″W / 39.62722°N 84.36583°W / 39.62722; -84.36583 (39.627133, -84.365951). According to the United States Census Bureau, the village has a total area of 3.6 square miles (9.3 km²), all of it land.