Buchanan is a city and the county seat of Haralson County, Georgia, United States. The population was 1,104 at the 2010 census, up fro…Buchanan is a city and the county seat of Haralson County, Georgia, United States. The population was 1,104 at the 2010 census, up from 941 at the 2000 census. Locally, the city's name is pronounced Buck-HAN-uhn.