Lineage. Established as Seattle Air Defense Sector, and organized, on 8 Jan 1958. Discontinued, and inactivated, on 1 Apr 1966. Redesignated as: Northwest Air Defense Sector, and activated on 1 Jul 1987; Western Air Defense Sector (ANG), 1 Jan 1995; Western Air Defense Sector (ANG), 1 Oct 1995;