Vashon is a census-designated place (CDP) in King County, Washington, United States. It covers an island alternately called Vashon Island or Vashon-Maury Island, the largest island in Puget Sound south of Admiralty Inlet. The population was 10,624 at the 2010 census. At 37 square miles (96 km2), it is about 60 percent larger in area than Manhattan, with about 1/150 the population. There are no bridges to connect the island with the mainland, a big factor contributing to the island's relative isolation and rural character.
The island was named on May 28, 1792, by the explorer George Vancouver after his friend James Vashon of the Royal Navy. At that time, Vashon Island was separate from the neighbouring Maury Island, but today the hamlet of Portage sits on an isthmus built by the U.S Army Corps of Engineers that connects the two.
Based on per capita income, Vashon ranks 32nd of 522 areas in the state of Washington to be ranked.