SR 309 begins at the Florida state line, southwest of Attapulgus.

It heads north to a partial interchange with US 27/US 84/SR 1/SR 38 (Wiregrass Georgia Parkway).

At this point, the four highways meet US 27 Business/SR 1 Business (North Broad Street).

The concurrency head northeast to an intersection with SR 311 (East River Road), just before leaving the city.

The highway continues to the northeast until it meets its northern terminus at SR 262 (Pelham Road), north of Climax, where the roadway continues as Mars Hill Church Road.