Established after the 1900 census, the Third District was represented by Democrats for most of the latter half of the 20th century, until Rep. Jolene Unsoeld was defeated by RepublicanLinda Smith as part of the Republican Revolution of 1994. Smith retired after two terms, and was succeeded by Democrat Brian Baird. Baird announced he wouldn't run for re-election in 2010, with Republican Jaime Herrera Beutler winning the now open seat in the 2010 general election 53%-47% against Democratic state Representative Denny Heck, who was subsequently elected in Washington's 10th congressional district. Herrera Beutler retained her seat 60%-40% over Democrat Jon T. Haugen in 2012. In 2014, she beat Democratic nominee Bob Dingethal by 61.5% to 38.5%.
In presidential elections, the 3rd District is rather competitive. It is the only part of western Washington that didn't swing heavily to the Democrats during the 1990s, and is one of the few districts in the area that cannot be considered safe for either party. It is home to Lewis County, far and away the most conservative county in western Washington. Additionally, most of the district is located in the Portland, Oregon, market; voting patterns there are somewhat different from those in the areas closer to Seattle. George W. Bush narrowly carried the district in 2000 with 48% of the vote and again in 2004 with 50%. The district swung Democratic in 2008, giving Barack Obama 52% of the vote and 46% to John McCain. However, redistricting (see below) extended the district further east and made it slightly more Republican than its predecessor; had the current boundaries been in effect for the 2008 election, Obama would have only defeated McCain by 50.9 percent to 47.1 percent. In 2012, it gave Mitt Romney 49.6% to Obama's 47.9%. In the 2016 presidential election, Republican nominee Donald Trump won the district 49.9% to Hillary Clinton's 42.5%.
The Washington State Redistricting Commission is charged with adjusting congressional and legislative district boundaries after each decennial census. Given Washington State's growth over the previous decade, Washington gained an additional congressional district for the 113th congress. The third district needed to lose 106,894 people in the redistricting process in order to meet the ideal population of 672,454. On September 13, 2011, the four voting commissioners on the Redistricting Commission submitted draft proposals for the congressional map. All four draft proposals left the entirety of Lewis, Wahkiakum, Cowlitz, and Clark Counties, and all or most of Skamania county in the 3rd district. In addition, each proposal added population from one or more of Pacific, Thurston, Pierce, or Klickitat counties.