William Ewart Humphrey was an American politician who served as a member of the United States House of Representatives from 1903 to 1917. He represented the state of Washington at large from 1903 to 1909 and the First Congressional District of Washington from 1909 to 1917. Humphrey also served as a member of the Federal Trade Commission from 1925 to 1933.

Washington's 1st congressional district encompasses parts of King and Snohomish counties. The district covers several cities in the north of the Seattle metropolitan area, east of Interstate 5, including parts of Bellevue, Marysville, and up north toward Arlington.