The first "ironclad" warship to be commissioned by the U.S. Navy. Arriving after the C.S.S. Virginia sank multiple wooden ships of the Union, the U.S.S. Monitor played a key role in the Battle of Hampton Roads, a battle which would attract attention from navies around the world. The first clashing of ironclad ships displayed terrible power as the C.S.S. Virginia destroyed multiple conventional navy ships with minimal damage, and was only stopped at the arrival of the U.S.S. Monitor. The battle ended in a stalemate, the Confederacy's efforts to thwart the Union's blockade against Virginia crushed.

An ordinary vessel in the employment of the U.S. Navy. The Merrimack never saw battle because it was sank by the U.S. Navy on the day of Virginia's secession to prevent capture by Confederate soldiers in the Norfolk Navy Yard. The soldiers raised the ship from the depths and used its frame to create the C.S.S. Virginia, a Confederate ironclad.

The CSS Tennessee, a 1273-ton ironclad ram, was constructed at Selma, Alabama. Her outfitting was finished at Mobile, where she was commissioned in February 1864, after she was launched in February 1863. As Admiral Franklin Buchanan's flagship, she was by far the most powerful force of Mobile Bay's naval defenses. The Federal Navy had to send ironclad monitors to the Gulf of Mexico to oppose her. The former Confederate ironclad was quickly renamed USS Tennessee by the Union Navy. Her combat damage was swiftly repaired, and she was used in the capture of Fort Morgan later that month. Tennessee was transported to New Orleans, Louisiana, for extensive repairs in the autumn of 1864. She afterwards served with the United States Navy's Mississippi Squadron until the Civil War ended. The USS Tennessee was decommissioned in August 1865 and scrapped in November 1867.