Decatur is a city in, and
county seat of,
DeKalb County,
Georgia, United States. With a population of 19,335 in the 2010 census, the city is sometimes assumed to be larger since multiple zip codes in unincorporated DeKalb County bear the Decatur name. It is an intown suburb of
Atlanta and part of the
Atlanta Metropolitan Area, and its public transportation is served by three
MARTA rail stations.