USS Massachusetts (BB-59), known as "Big Mamie" to her crewmembers during World War II, was a battleship of the second South Dakota class. She was the seventh ship of the United States Navy to be named in honor of the sixth state, and one of two ships of her class (along with her sister Alabama) to be donated for use as a museum ship. Among the ships armed with 16-in (406 mm) guns during World War II, Massachusetts stands out because it is believed that she fired the US Navy's first and last 16-in (406 mm) shells of the war.