The first ''Iowa'' was a monitor originally named ''Ammonoosuc'' that was never commissioned. She was renamed ''Iowa'' before being sold.
USS Iowa (BB-4) , the second ''Iowa'', was a battleship that saw action during the Spanish-American War.
USS Iowa (BB-53) , the third ''Iowa'' was a battleship already under construction when she was canceled by the Washington Naval Treaty.
USS Iowa (BB-61) , the fourth ''Iowa'' was the lead ship in her class of battleships, and saw action during World War II, the Korean War, and the Vietnam War.
