Washington's 1st congressional district

U. S. House district for Washington

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. In presidential elections, the 1st district has leaned Democratic. Under the old boundaries, Al Gore and John Kerry narrowly carried the district in 2000 and 2004, with 48% and 51% of the vote, respectively. In 2008, Barack Obama swept the district with 55.60% of the vote, while John McCain received 42%. Similarly, Hillary Clinton won the district in 2016 with 54% of the vote over Donald Trump with 38%, and in 2020 Joe Biden polled 59% to 38% for Donald Trump.

Prior to the 2012 redistricting, the district encompassed part of Northwest Seattle and largely suburban areas north and east of Seattle, including Shoreline, Edmonds, Lynnwood, Mountlake Terrace, Kenmore, Bothell, Kirkland, and Redmond, as well as Bainbridge Island and part of the Kitsap Peninsula. Until March 20, 2012, it was represented by Democrat Jay Inslee from Bainbridge Island. Inslee resigned to focus on his run for Governor of the state; the seat remained vacant until the special election that coincided with the November 2012 general election. The former House seat of powerful U. S. Senator Warren G. Magnuson, the district was a swing district throughout much of the 1990s, changing hands and parties three times in four elections. Before the election of future U. S. Senator Maria Cantwell in 1992, the district had been in Republican hands for 40 years (and 42 of the previous 46 years). Since the 1998 election, when Inslee was first elected, the growing Democratic trend in the Seattle area enabled him to turn it into a fairly safe seat. He had been re elected six times, with little difficulty, most recently in 2010.

The 2012 redistricting drastically changed the 1st district. Much of this area was previously part of the 2nd district, but in the new map, the 2nd has shrunk significantly. Jay Inslee (D) was the representative of the 1st district until resigning to run for governor of the state, but most of the district has been represented by Rick Larsen (D), of the 2nd district, in the past. Soon after the 2012 general election polls closed, the Seattle Times and national news organizations called the district for Democrat Suzan DelBene, defeating Republican John Koster with a margin that the Seattle Times called "unexpectedly decisive", reflecting the difficulty of predicting the vote in the new district. The certified results confirmed her significant margin. DelBene also won the election for the remainder of Inslee's term in the old first district, and after being sworn in on November 13, 2012.

Beginning in 1909, members were elected from districted seats, instead of at large statewide. (See .) Member Party Years Congress Electoral history District location District established March 4, 1909 William E. Humphrey Republican March 4, 1909 –March 3, 1917 Redistricted from the and re elected in 1908. Re elected in 1910. Re elected in 1912. Re elected in 1914. Retired to run for U. S. senator. John Franklin Miller Republican March 4, 1917 –March 3, 1931 Elected in 1916. Re elected in 1918. Re elected in 1920. Re elected in 1922. Re elected in 1924. Re elected in 1926. Re elected in 1928. Lost renomination. Ralph Horr Republican March 4, 1931 –March 3, 1933 Elected in 1930. Lost renomination. Marion Zioncheck Democratic March 4, 1933 –August 7, 1936 Elected in 1932. Re elected in 1934. Died. Vacant August 7, 1936 –January 3, 1937 Warren Magnuson Democratic January 3, 1937 –December 13, 1944 Elected in 1936. Re elected in 1938. Re elected in 1940. Re elected in 1942. Retired to run for U. S. senator and resigned when elected. Vacant December 13, 1944 –January 3, 1945 Hugh De Lacy Democratic January 3, 1945 –January 3, 1947 Elected in 1944. Lost re election. Homer Jones Republican January 3, 1947 –January 3, 1949 Elected in 1946. Lost re election. Hugh Mitchell Democratic January 3, 1949 –January 3, 1953 Elected in 1948. Re elected in 1950. Retired to run for Governor of Washington. Thomas Pelly Republican January 3, 1953 –January 3, 1973 Elected in 1952. Re elected in 1954. Re elected in 1956. Re elected in 1958. Re elected in 1960. Re elected in 1962. Re elected in 1964. Re elected in 1966. Re elected in 1968. Re elected in 1970. Retired. Joel Pritchard Republican January 3, 1973 –January 3, 1985 Elected in 1972. Re elected in 1974. Re elected in 1976. Re elected in 1978. Re elected in 1980. Re elected in 1982. Retired. John Miller Republican January 3, 1985 –January 3, 1993 Elected in 1984. Re elected in 1986. Re elected in 1988. Re elected in 1990. Retired. Maria Cantwell Democratic January 3, 1993 –January 3, 1995 Elected in 1992. Lost re election. Rick White Republican January 3, 1995 –January 3, 1999 Elected in 1994. Re elected in 1996. Lost re election. Jay Inslee Democratic January 3, 1999 –March 20, 2012 Elected in 1998. Re elected in 2000. Re elected in 2002. Re elected in 2004. Re elected in 2006. Re elected in 2008. Re elected in 2010. Resigned to run for Governor of Washington. 2003–2013 Vacant March 20, 2012 –November 6, 2012 Suzan DelBene Democratic November 6, 2012 –present Elected to finish Inslee's term. Elected on the same day in 2012 to the next term. Re elected in 2014. Re elected in 2016. Re elected in 2018. Re elected in 2020. Re elected in 2022. 2013–2023 2023–present