O.C.G.A. § 21-2-403

At all primaries and elections the polls shall be opened at 7:00 A.M. eastern standard time or eastern daylight time, whichever is applicable, and shall remain open continuously until 7:00 P.M. eastern standard time or eastern daylight time, whichever is applicable, at which time they shall be closed; provided, however, that, in all cities having a population of 300,000 or more according to the United States decennial census of 1970 or any future such census, the polls shall remain open continuously until 8:00 P.M. eastern standard time or eastern daylight time, whichever is applicable, during the cities' general elections, at which time they shall be closed and provided, further, that, in a special election held to fill a vacancy in an office in which the district represented by such office lies wholly within the boundaries of a city, the polls shall close at the same time as for a municipal general election in such city.