Like Oregon, the State of Washington conducts all elections via vote-by-mail. Originally, absentee ballots in Washington were mailed prior to election day to those voters who contacted their local county by indicating that they would be unable to vote at their local polling place on election day.
In 1993, the state began allowing all voters to vote by mail on a permanent basis. Since that time, voting by mail had gained in popularity, and the term "absentee ballot" had become synonymous with voting by mail. According to the Secretary of State, in 2006, over 88% of all voters cast votes using the vote-by-mail method. By then, many counties had made the switch to conducting their elections entirely by mail. The state's two largest counties (in terms of number of voters), King and Pierce, were the last two counties in the state to switch to all-mail voting. When the King County Council approved the switch in 2009, the county became the largest in the nation, in terms of number of voters, where elections are conducted entirely by mail. Pierce County's resistance to making the change led to action by the Washington State Legislature in 2011 that required the county to be in line with the rest of the state, thus making the entire state a "vote-by-mail" state.
Many counties provide drop boxes throughout the county to allow voters to drop off their ballot on or prior to election day, rather than paying postage by sending it through the mail. Ballots returned by mail need only be postmarked by election date, resulting in ballots being received by election officials over several days following an actual election.