Topsail Island Topsail Island is a 26 - mile ( 41 . 8 km ) long barrier island off the coast of North Carolina , USA just south of Camp Lejeune , the Bogue Banks , and the Outer Banks . It contains the communities of North Topsail Beach , Surf City and Topsail Beach . Along with its thick maritime forest s , Topsail Island is also a sanctuary for sea turtles and known for its beautiful beaches . The island lies in Stump Sound Township , Onslow County in the north , and in Topsail Township , Pender County in the south . There are only two ways on and off the island : the first is a high rise bridge on the North End and the second is a swing bridge that brings you into Surf City . Name origin . Topsail Island ' s name is supposedly derived from its nefarious history , however , this is still debatable among the locals on the Island . According to popular belief , pirates used to hide in the channel between the island and the mainland waiting for merchant ships loaded with goods to pass . The pirates would attack the ships and claim the cargo as their own . Eventually the merchants became aware of the hiding place and began looking for the topsail , which was supposedly the only part of the pirate ship that could be seen by the passing ' victim . ' There is a legend that Blackbeard hid his treasure on Topsail Island and that prior to WWII , treasure hunters searched for the hidden gems and gold throughout the islands ' maritime forests . Operation Bumblebee . At the end of World War II the Navy began a joint venture with Johns Hopkins University and established the US Naval Ordnance Test Facilities at Topsail Island , North Carolina , for Operation Bumblebee , a top - secret , experimental project to develop and test ramjet missiles , which advanced the Nation ' s jet aircraft and missile programs . So successful were the tests conducted at the Topsail Island site that the ramjet proved its value , opened the way for the advance of supersonic jet aircraft design and brought the United States to the threshold of modern space technology with the Talos , Terrier , Tartar and Sea Sparrow missiles aboard naval vessels . Named after a bumblebee , which although aerodynamically is unable to fly , does not know this and flies anyway , this operation lead to the maturing of supersonic aircraft and shipboard missile design in the mid - 20th century . Topsail Island was the third of three widespread test sites established along the Atlantic seaboard in the closing years of World War II , and the first permanent ground for missile testing . The Topsail Island site , placed in operation in March 1947 , incorporated rigid structures that were designed and built for specific uses related to the assembly , firing , monitoring and perfecting of experimental ramjet missiles . The buildings associated with this testing , the Assembly Building , Facility Control Tower and Observation Tower No . 2 possess exceptional importance because they are the only aboveground resources remaining at these three sites where the Nation ' s burgeoning ramjet missile program grew from experimentation to maturity . The Assembly Building is a one - and - a - half - story masonry building and the Control Tower is a three - story reinforced concrete building . Observation Tower # 2 is an unaltered example of the seven instrument towers erected on Topsail Island . Naval and Marine personnel , numbering 500 men , and led by Lieutenant Commander Tad Stanwick , arrived at the site by mid - 1946 to begin installation of the facilities needed for the testing . During the next 18 months , an estimated 200 experimental rockets , each measuring six inches in diameter and between three and 13 feet in length , were fabricated at the Assembly Building , dispatched to the launch site , and fired along a northeasterly angular deflection of 15 degrees to the shoreline for a maximum clear distance of 40 miles . Despite the initial success of the US Naval Ordnance Testing facility at Topsail Island over its 18 - month span , its location did not fulfill completely the needs of a permanent base because weather conditions and increased sea traffic interfered with testing , and the facility was abandoned and its equipment moved to other sites .