when did washington became a state?
<answer> 11 November 1889 <context> Washington became a state on 11 November 1889. It had previously been the Washington Territory, split from the Oregon Territory in 1848.orth Dakota and South Dakota were admitted to the union on November 2, 1889 as the 39th and 40th states. Montana was admitted to the union on November 8, 1889 as the 41st. st … ate. Washington was admitted to the union on November 11, 1889 as the 42nd state.