A treaty battleship was a battleship built in the 1920s or 1930s under the terms of one of a number of international treaties governing warship construction. Many of these ships played an active role in the Second World War, but few survived long after it.
HMS Nelson was the first treaty battleship
Signing of the Washington Naval Treaty
Colorado-class battleship
The Colorado-class battleships were a group of four United States Navy super-dreadnoughts, the last of its pre-Treaty battleships. Designed during World War I, their construction overlapped the end of that conflict and continued in its immediate aftermath. Though all four keels were laid, only three ships entered service: Colorado, Maryland, and West Virginia. Washington was over 75% completed when she was canceled under the terms of the Washington Naval Treaty in 1922. As such, the 16" gun Colorado-class ships were the last and most powerful battleships built by the U.S. Navy until the North Carolina class entered service on the eve of World War II.
Colorado steaming off New York City, c. 1932
Hull of Maryland under construction c. 1917
USS Maryland in March 1944
USS West Virginia in her final configuration, June 1944. Note 5 in/38 twin turrets and number of AA guns