John Adolphus Dahlgren, born 13 November 1809 in Philadelphia, Pa., was appointed a midshipman 1 February 1826, and early became interested in the problems of ordnance. He developed the famous Dahlgren gun, perfected howitzers for use afloat and ashore, o rganized the Naval Gun Factory, and wrote several significant books on ordnance. From the outbreak of the Civil War until July 1862 he served as Commandant of the Washington Navy Yard where President Lincoln often conferred with him. He then became Chief of the Bureau of Ordnance and on 7 February 1863 was promoted to the rank of Rear Admiral. In command of the South Atlantic Blockading Squadron (7 July 1863-17 June 1866), he participated in the bombardment of Fort Wagner and cooperated with Sherman in th e capture of Savannah and Charleston. After a tour of duty in command of the South Pacific Squadron (1866-1868), he returned to Washington again as Chief of the Bureau of Ordnance. Rear Admiral Dahlgren resigned this job a year later to return to the comm and of the Navy Yard and Gun Factory. He died in Washington 12 July 1870.

The third Dahlgren (DLG-12) was launched 16 March 1960 by Philadelphia Naval Shipyard, sponsored by Mrs. Katharine D. Cromwell, granddaughter of Rear Admiral Dahlgren; and commissioned 8 April 1961, Commander C. E. Landis in command.