The Portsmouth Subdivision is a railroad line owned by CSX Transportation in Virginia and North Carolina. The line currently runs from Portsmouth, Virginia, to Garysburg, North Carolina on the Roanoke River, a distance of 75.8 miles. At Garysburg, the line connects to CSX's A Line (North End Subdivision). The Portsmouth Subdivision previously crossed the Roanoke River and continued west to Norlina, North Carolina under CSX predecessor, the Seaboard Air Line Railroad.