There has been a Navy Yard in Philadelphia since 1800 when the Secretary of the Navy purchased ground for that purpose between Washington and Reed Streets and thence East to the Delaware River. Thirty-five vessels of war were built there between 1815 and 1875. But the growth of the City and the need for a larger Naval establishment after the Civil War made that area impracticable. The Navy moved to League Island in 1876, to more spacious grounds, which it eventually developed into one of the largest naval stations in the world. Although many of the buildings and much of the equipment from the old Yard was moved here, not a great deal was done for many years to develop the land. During and after the Spanish-American War, considerable work was done in laying roads and sewers and establishing permanent buildings. But it was not until 1917 that the first ship was built, the USS HENDERSON, a transport. During the first world war, two more shipways were constructed as well as supply warehouses. After the war, the Washington Conference for Limitation of Armament caused the discontinuance of two large battle cruisers (45,000 tons), and indeed, during the twenties, there was little activity, the Yard existing mainly on modernization and upkeep work. In 1931, however, the Yard came into its own as "the primary shipbuilding Yard" with the laying of the keel of the cruiser USS MINNEAPOLIS. From then on, there has been a succession of ships coming off the building ways. The USS MINNEAPOLIS was followed by the destroyer AYLWIN, four Coast Guard cutters, the CAMPBELL, INGHAM, DUANE and TANEY, the destroyers CASSIN and SHAW, the heavy cruiser WICHITA and light cruiser PHILADELPHIA in 1935, and then in 1938 the first new battleship of our modern fleet, the USS WASHINGTON. The most noticeable features of the Yard between the wars were the more than 90 destroyers and submarines, laid up out of commission in the Reserve Basin. When the President declared a limited emergency in the fall of 1939, after the German invasion of Poland, the Yard passed quickly into a war time tempo and the ship construction program was speeded. To meet the requirements of this program, however, it was necessary to create the facilities to build the ships. Two drydocks, Nos. 4 and 5, were rushed to completion in the winter of 1942-43, while the entire west end of the Yard was reclaimed from a muddy swamp. More and bigger weight handling facilities were added, including a 350 ton crane. New shops and office buildings were created almost overnight to provide space for the new personnel reporting. A marine railway was built on which smaller vessels could be hauled out of the water on to the shore. To serve for and safeguard the Yard personnel, a large police force, rehabilitated fire department, cafeteria system and transportation facilities were provided.