first Pensacola was a screw steamer launched by the Pensacola Navy Yard
15 August 1859 and commissioned there 5 December 1859 for towing to Washington
Navy Yard for installation of machinery; decommissioned 31 January 1860;
commissioned in full 16 September 1861, Capt. Henry W. Morris in command.
Pensacola departed Alexandria, Va., 11 January 1862 for the Gulf of Mexico to join Flag Officer Farragut's newly created West Gulf Blockading Squadron. She steamed with that fleet in the historic dash past Confederate forts St. Philip and Jackson which protected New Orleans 24 April and the next day engaged batteries below that great Confederate metropolis. On the 26th, a landing party raised the Union flag over the mint at New Orleans. During the next two years, she helped guard the lower Mississippi, returning to New York Navy Yard where she decommissioned 29 April 1864 for the installation of new and improved machinery.
Recommissioned 16 August 1866, Pensacola sailed round Cape Horn to join the Pacific Squadron, serving from time to time as flagship. Her cruising ranged from Chile to Puget Sound and west to Hawaii. But for two periods in ordinary. 15 February 1870 to 14 October 1871 and 31 December 1873 to 13 July 1874, she continued this duty until detached from the Pacific squadron in June 1883. Departing Callao, Peru 18 July she sailed west across the Pacific and Indian oceans, transited the Suez Canal, and steamed the length of the Mediterranean, before crossing the Atlantic to arrive in Hampton Roads 4 May 1884. She decommissioned at Norfolk on the 23rd.
Recommissioned 4 April 1885, Pensacola operated in European waters until returning to Norfolk in February 1888 for repairs. Operations along the Atlantic Coast and a cruise along the coast of Africa ended when the ship returned to New York in May 1890. In August she headed back to familiar haunts in the Pacific arriving San Francisco 10 august 1891. Following a visit to Hawaii she decommissioned at Mare Island 18 April 1892.
Recommissioned 22 November 1898, Pensacola served as a training ship for Naval apprentices until going back into ordinary 31 May 1899. She was back in commission 14 July 1901, subsequently used as a receiving ship at Yerba Buena Training Station, San Francisco until finally decommissioning 6 December 1911 and struck from the Navy Register 23 December. She was burned and sunk by the Navy in San Francisco Bay near Hunter's Point early in May 1912.