Union is a small census-designated place in Mason County, Washington, United States.Census reported a population of 631 inhabitants in the 2010 census.
Union was founded and named in 1858 by merchants Willson and Anderson. In 1889, logging pioneer John McReavy platted Union City on Hood Canal’s south shore, neighbor to the Native American communities that had gathered where Hood Canal makes its great bend. This area is the homeland of the native Skokomish Tribe . The Skokomish River flows off the nearby Olympic Mountains, flowing into Hood Canal just south of Union.