Atlanta is a city in Macon County, Missouri, United States. The population was 379 at the 2020 census. Atlanta was platted in 1858. The comm…Atlanta is a city in Macon County, Missouri, United States. The population was 379 at the 2020 census. Atlanta was platted in 1858. The community was named after Atlanta, Georgia. A post office called Atlanta has been in operation since 1868.