USS Osage, a 523-ton Neosho class single-turret ironclad river monitor, was built at Carondelet, Missouri. Commissioned in July 1863, she operated in the Mississippi River area in 1863 and 1864, including participation in expeditions up Louisiana's Black and Ouachita Rivers in February-March 1864 and the Red River in March-May of that year. In February 1865, Osage was transferred to the West Gulf Blockading Squadron for employment in Mobile Bay. In late March she took part in an attack on Spanish Fort, near Mobile, Alabama. While engaged in that operation on 29 March 1865, USS Osage struck a Confederate "torpedo" and was sunk in the Blakely River. Her hulk was later raised and was sold in November 1867.