USS Manhattan, a 2100-ton Canonicus class monitor, was built at Jersey City, New Jersey. She was commissioned in June 1864 and immediately sent to the Gulf of Mexico to take part in the planned attack on Mobile Bay, Alabama. On 5 August 1864, in company with the monitors Tecumseh, Winnebago and Chickasaw, she bombarded Fort Morgan as Rear Admiral Farragut's squadron entered Mobile Bay. Later in the day, Manhattan's gunfire helped force the surrender of the Confederate ironclad Tennessee. She also shelled Fort Morgan during the seige that followed.

In November 1864, Manhattan went to New Orleans, Louisiana, for service on the Mississippi River and later on the Red River. She was decommissioned at New Orleans in August 1865 and was briefly renamed Neptune in June-August 1869, while still laid up. Later transferred to Key West, Florida, and Philadelphia, Pennsylvania, Manhattan remained "in ordinary" until November 1873 when she was recommissioned. Following service in Florida and South Carolina waters, in 1877 she went to the James River, Virginia, where she remained until 1888. USS Manhattan spent her last years laid up at Philadelphia's League Island Navy Yard and was sold for scrapping in March 1902.