USS Onondaga was launched 29 July 1863 by Continental Iron Works, Greenpoint, N. Y., under subcontract from George W. Quintard; sponsored by Miss Sally Sedgwick, daughter of former U. S. Representative Charles Baldwin Sedgwick, who codified naval laws for the Navy Department. She was commissioned at New York Navy Yard on 24 March 1864, Captain Melancthon Smith her first commanding officer.
With Mattabesset, the new monitor departed New York 21 April 1864, and arrived at Hampton Roads two days later. Operating primarily in the James River Flotilla, Onondaga supported General Ulysses Grant’s drive on Richmond. On 24 November with Mahopac she engaged Southern batteries on the James at Howlett’s, Virginia, and resumed the attack 5 and 6 December.
Early in January much of the Union strength was withdrawn from the James as Admiral David D. Porter assembled his powerful fleet for the forthcoming attack on Fort Fisher, North Carolina, which protected Wilmington. Onondaga was the only monitor left to guard Union forces on and along the James against Flag Officer John K. Mitchell’s Confederate James River Squadron. When the Southern force steamed down river to attack the weakened Union forces there afloat, the monitor dropped downstream to a position affording her greater maneuverability. She and her supporting gunboats awaited the Southern attack only to have the Confederate thrust blunted when Mitchell’s ironclads Virginia II and Richmond, gunboat Drewry, and torpedo boat Scorpion all ran aground trying to pass obstructions at Trent’s Reach. After attacks by Northern shore batteries and Onondaga, Drewry exploded, Scorpion was abandoned, and the two Southern ironclads withdrew upriver when they were refloated the next day.
After continuing to support Union troops fighting to take the Confederate capital until General Robert E. Lee was forced to abandon Richmond, Onondaga steamed north and decommissioned at New York 8 June 1865 and was laid up at League Island, Pennsylvania. By an Act of Congress approved 7 March 1867, the monitor was sold to her builder, G. W. Quintard and subsequently resold to France for service in the French Navy under the same name. There her American armament was removed and replaced with 9.4-inch rifled guns. Onondaga, whose iron hull helped to make her the longest-lived of the larger American-built Civil War era monitors, was scrapped in about 1903-1904.
Part of the text is incorporated from the United States Navy's Dictionary of American Naval Fighting Ships, a work in the public domain.
Images of USS Onondaga during the James River operations of 1864-5