New Lebanon is a village in Montgomery County, Ohio, United States. The population was 3,796 at the 2020 census. It is part of the Dayton Metropolitan Statistical Area. New Lebanon was platted in 1843. A post office called Medill was established in 1847, and the name was changed to New Lebanon in 1849. New Lebanon was incorporated as a village i…New Lebanon is a village in Montgomery County, Ohio, United States. The population was 3,796 at the 2020 census. It is part of the Dayton Metropolitan Statistical Area. New Lebanon was platted in 1843. A post office called Medill was established in 1847, and the name was changed to New Lebanon in 1849. New Lebanon was incorporated as a village in 1878.