High Quality Content by WIKIPEDIA articles! NC 400 is the shortest primary state highway in North Carolina. It is 0.93 miles (1.50 km) long and is entirely within the town of Manteo, North Carolina on Roanoke Island. The route traverses from its western terminus at U.S. Route 64 to the Elizabeth II vessel (State Historic Site) docked on Ice Plant Island, located in Shallowbag Bay. Unlike other state routes, all of the NC 400 markers have brown recreational backgrounds. The route is split among two one-way streets: eastbound and westbound.