The flag was officially adopted on March 5, 1923, and has been a symbol of Washington ever since. Washington had achieved statehood in 1889, but did not have an official flag at the time. The Washington chapter of the Daughters of the American Revolution designed the flag in 1915 and campaigned for its adoption by the Washington State Legislature in the early 1920s.
The state flag has undergone minor revisions since its adoption, including the use of standardized colors in 1955 and a modernized seal in 1967.
Washington was nicknamed “The Evergreen State” by pioneer C.T. Conover, a Seattle realtor and historian, for its abundant evergreen forests. This nickname appeared on the state’s commemorative state quarter.