Hamler is a village in Henry County, Ohio, United States. The population was 600 at the 2020 census. Hamler is a rural farming community in Northwest Ohio about 40 miles southwest of Toledo, Ohio. It is located at the intersection of the former Baltimore and Ohio and former Detroit, Toledo and Ironton railroads and the intersection of Ohio State Rout…Hamler is a village in Henry County, Ohio, United States. The population was 600 at the 2020 census. Hamler is a rural farming community in Northwest Ohio about 40 miles southwest of Toledo, Ohio. It is located at the intersection of the former Baltimore and Ohio and former Detroit, Toledo and Ironton railroads and the intersection of Ohio State Route 109 and Ohio State Route 18.