USS Puritan was one of two ocean-going ironclad monitors designed by John Ericsson during the American Civil War of 1861–1865.

The engine drove two propeller shafts using steam provided by six Martin water-tube boilers and the designed speed was 15 knots (28 km/h; 17 mph).

[1] Puritan's armor scheme was identical to that of Dictator, the other ocean-going monitor ordered at the same time.

[3] Buoyed by the victory gained by Ericsson's Monitor during the Battle of Hampton Roads in early March 1862, the Navy Department decided later that month to build several ocean-going monitors in case the British or the French decided to intervene in the war.

Although Congress was informed by the Navy Department that the Civil War-era ship was being repaired, a new iron-hulled monitor of the same name was built with repair money and the proceeds of her sale because Congress refused to fund any new construction at this time.