USS Choctaw, a 1004-ton ironclad river gunboat and ram, was originally built in 1856 at New Albany, Indiana, as a side-wheel merchant steamer. Acquired by the Government in September 1862, her conversion to a warship was begun using plans by Commodore William D. Porter but these were altered while work was underway. Commissioned in March 1863, Choctaw was a singular-looking vessel, probably the most imposing in appearance of any of her Mississippi Squadron contemporaries. In actuality, however, she was weakly-armored and very slow.

Choctaw's operational career began with a bombardment of Haynes' Bluff, on the Yazoo River, Mississippi, in late April and early May 1863. She was hit 53 times in this action, with many shots penetrating her armor, but casualties among her crew were light. Later in May, she participated in the capture of Yazoo City and the destruction of the Confederate Navy Yard there. In March-May 1864, Choctaw was part of the large Naval force that took part in a major campaign on the Red River, in Louisiana. She was decommissioned in July 1865, after the end of the Civil War, and was sold in March 1866.