25th Air Division The 25th Air Division is an inactive United States Air Force intermediate echelon command and control organization . It was last assigned to First Air Force , Tactical Air Command ( ADTAC ) . It was inactivated on 30 September 1990 at McChord Air Force Base , Washington . History . The command was activated on 25 October 1948 , being the first Air Division for air defense . Its headquarters was at Silver Lake , near Everett , Washington under Continental Air Forces ( ConAC ) . The 25th AD did not assume any command responsibilities until 1949 when it became an intermediate level command under the Air Defense Command , Western Air Defense Force . Its initial Area of Responsibility ( AOR ) was a large area of the northwest Continental United States , from the 103rd meridian west and north of the 42nd parallel north . This encompassed an area consisting of the states of Washington , Oregon , Idaho , Montana and Wyoming and the western parts of North and South Dakota as well as Nebraska . During the 1950s the AOR of the 25th AD changed frequently , but its core area always included the area of Washington State west of the Cascade Mountains . On 1 January 1951 , Air Defense Command regained major command status , and the 25th AD was one of four Air Divisions assigned to the new command . Later that year , on 15 September HQ 25th AD was moved from Silver Lake AFS to McChord AFB , near Tacoma , Washington . Beginning on 1 January 1958 , it the command organization for the Seattle Air Defense Sector Semi Automatic Ground Environment ( SAGE ) Data Center ( DC - 12 ) at McChord AFB . A few months later , on 1 September , the Portland Air Defense Sector , with its SAGE Direction Center ( DC - 13 ) at Adair AFS , Oregon also came under the 25th AD ; on 8 September the Spokane Air Defense Sector and DC - 15 at Larson AFB toned the 25th AD . In 1959 , the Reno Air Defense Sector and DC - 16 at Stead AFB , Nevada was also incorporated . During the Cold War era , the 25th AD equipped , administered , trained and provided air defense combat ready forces within the northwestern United States . It exercised command jurisdiction over assigned units , installations , and facilities and provided and maintained facilities for the Air Division control center . In addition , the division and its subordinate units also participated in numerous tactical air defense training exercises . In the late 1950s , the Division also controlled United States - built radar stations in Western Canada as part of the Pinetree Line . These stations were turned over to the Royal Canadian Air Force in the early 1960s . In May 1960 , SAGE Combat Center Number 3 ( CC - 03 ) became operational at McChord AFB , bringing these separate Direction Centers under a unified center under the 25th AD . In July , DC - 16 at Stead AFB was reassigned to the 28th Air Division at Hamilton AFB , California and the inactivation of the Western Air Defense Force brought the 25th AD directly under the control of Air Defense Command . In 1966 it was assigned to Headquarters , Fourth Air Force at Hamilton AFB , although it remained stationed at McChord AFB . It also replaced the Seattle Air Defense Sector in 1966 . Assumed additional designation of 25th NORAD Region after activation of the NORAD Combat Operations Center at Cheyenne Mountain , Colorado and reporting was transferred to NORAD from ADC at Ent AFB in April 1966 . The division was a major part of Air Defense Command , and later Aerospace Defense Command ( ADCOM ) in 1968 . In 1979 it was incorporated into Tactical Air Command with the inactivation of ADCOM as a major command . Under Air Defense , Tactical Air Command ( ADTAC ) . In 1985 most active - duty units of ADCOM were inactivated or reassigned to other missions , and the air defense mission came under Air Force Reserve and Air National Guard units under First Air Force . It continued its mission until 1990 , when the 25 AD was inactivated , its mission and components becoming part of the First Air Force Northwest Air Defense Sector .