 US 78 travels through portions of Haralson, Carroll, Douglas, Cobb, Fulton, DeKalb, Gwinnett, Walton, Oconee, Clarke, Oglethorpe, Wilkes, McDuffie, Columbia, and Richmond counties.Various portions of the highway, from the Alabama state line into Atlanta, were part of the historic Bankhead Highway, a cross-country automobile highway connecting San Diego and Washington, D.C..It was part of the National Auto Trail system.