Union City is located in Fulton County and was incorporated on August 17, 1908 when the city was in Campbell County. Campbell County went bankrupt during the Great Depression and merged with Fulton County.

Prior to the incorporation of Union City, District Attorney Carmichael was instrumental in convincing the Farmer’s Union to locate its national headquarters to the city. It was from this organization that the city received its name.

Union City was named when the area became the meeting place of two railroads, the Atlanta and West Point and the Atlanta Birmingham and Atlantic Railroads.