In Henry County US 23 continues north concurrently with SR 42. US 23 follows Moreland Avenue concurrently with SR 42 in Clayton County and metro Atlanta, running for several miles in a perfectly straight and due north–south line, which is also the Fulton–DeKalb county line. The highway then turns onto Ponce de Leon Avenue, splitting from SR 42, to follow US 29, US 78 and US 278. Farther along, US 23 turns onto Clairemont Avenue and onto Buford Highway to leave metro Atlanta. In Buford, US 23 turns right onto SR 20, then onto I-985. The highway intersects US 129 in Gainesville. At the end of I-985, US 23 then continues concurrently with SR 365 north.