The route connects Byron with the Atlanta metropolitan area, via Forsyth, McDonough, and Forest Park.The three routes travel to the north-northwest into the town of Musella, where SR 42 splits off to the north-northeast and enters Monroe County.US 23/SR 42 resume their north-northwest routing, passing Sylvan Grove Hospital before leaving town.They skirt along the eastern edge of Fort Gillem and pass by Conley Park, just before entering DeKalb County.They pass by Chestnut Hill Cemetery and meet the eastern terminus of SR 42 Spur (McDonough Boulevard SE).Then, it heads fairly northward, passing between Emory University and Herbert Taylor Park and crosses over South Peachtree Creek.It begins at an interchange with SR 10 (John Lewis Freedom Parkway NE) east-northeast of Atlanta Medical Center.It travels northeast through Freedom Park until it meets its eastern terminus, an intersection with US 23/SR 42 (Moreland Avenue SE).It travels southeast and meets the northern terminus of SR 54 Conn. (Sawtell Avenue SE) on the northeastern corner of the United States Penitentiary.