Roads and streets are currently vacated by King County Council action. To find the actual Council ordinance authorizing the vacation, see the county's Legislative Files or contact the King County Archives.
Road vacations in unincorporated King County prior to May 1969 were sometimes made by resolutions of the King County Commissioners. More often they were made by direct orders (sometimes abbreviated "Ord." on old documents) of the Commissioners. Texts of road vacation orders can be found in, and copied out of, the Commissioners' Proceedings. For assistance in locating a road vacation order, please contact the King County Archives. It is very helpful if you can give Archives staff a vacation order number or an approximate date of the road vacation.
Another source of information is the Commissioner's road vacation files. These files are arranged by vacation order number (1 through 1413). The files usually contain the original signed road vacation order and may also include supporting documentation such as petitions, maps, engineers' reports and correspondence. These records are currently held at the Puget Sound [state] Regional Archives in Bellevue. Please contact the Regional Archives (external link) for additional information.
When unincorporated areas of King County incorporate into municipalities, the municipalities assume responsibility for road actions such as vacations. Your municipality's ordinance files may contain relevant information.