Quote: I believe the IOWA was indeed the last battleship built and was decomissioned in 1990.
There were four Iowa class battleships built during WWII. BB61 Iowa BB62 New Jersey BB63 Missouri BB64 Wisconsin
Two more were planned, but scrapped after partially completed. The Montana class would have been built after the Iowas if WWII had lasted longer. When referring to a class of ships in the US Navy, usually the first in the class is the "namesake" of the class. The numbering of the rest of the class is usually sequential, in order, from the first to the last. Battleships built to the same design as the Iowa, were referred to as Iowa or BB61 or just 61 class battleships. There are very few exceptions to this numbering rule. I do remember the Coontz class destroyers (DDG-40 Class) a few years back, one of the members of that class was the Farragut (DDG-37) but I'm pretty sure that had to do with the fact they were reclassified by the US Navy from a DLG to a DDG and for some reason the hull numbers did not line up with the order of comissioning. My point is, the Iowa was not the last of the class, she was the first.
The whole Last Battleship title is such a grey area. Technically the HMS Vanguard could be considered the Last Battleship since she was comissioned in 1946. In order of hull numbers, USS Wisconsin is the Last Battleship. Wisconsin is also a few feet longer than the other Iowas on account of a collision with the destroyer Eaton. The bow of the unfinished batleship Kentucky (BB66) was grafted on to replace Wisconsin's damaged bow. This added some length to the Wisky. Ironically they called Wisconsin "Wisky" even before she had a part of the Kentucky's hull to call her own.
Battleship Missouri BB63 was the last comissioned battleship in the US Navy, only because NY Navy Yard had a slower build time. Had the Philadelphia Navy Yard dragged their feet for a few days, Wisconsin would have been completed after Missouri.
Just in case the discussion gets REALLY technical, neither the Missouri nor the New Jersey can have the title of "the Last Battleship to ever put to sea" as they have now attained a "museum" status and can never be reactivated. Technically both the Iowa and Wisconsin are still maintained in a "reserve" status, the Navy still owns and maintains both ships. This is why you cannot tour the inside of the Wisconsin, she is still a US Navy ship and the interior is a restricted area. Although it is unlikely she will ever be reactivated, their is always a slim chance with that reserve status. There cannot be a "last battleship that ever put to sea" title while two battleships are still in the US Navy reserve fleet.