Washington's 9th congressional district encompasses a long, somewhat narrow area in Western Washington, through the densely populated central Puget Sound region, from Auburn and Federal Way in the south to parts of Seattle and Bellevue in the north.

Since being first elected in 1996, Smith's moderate voting record and a strong Democratic trend in the Puget Sound region turned the formerly contentious district into a fairly safe Democratic seat.

In 2011, the state began the process of redistricting in response to population changes determined by the 2010 census.

In the final report by the bipartisan redistricting commission issued in January 2012, the 9th district shifted to the north.

The new district covered Bellevue, Southeast Seattle, and Mercer Island, but only went as far south as the southern tip of Commencement Bay in Tacoma.