Osceola Air Force Station (ADC ID: P-35, NORAD ID: Z-35) is a closed

United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

General Surveillance Radar station. It is located south-southeast of

Osceola, Wisconsin Osceola ( ) is a village in Polk County, Wisconsin, United States. The population was 2,765 at the 2020 census. Located mostly within the Town of Osceola, the village sits on the border with Minnesota, separated by the St. Croix River. It is ...

. It was closed in 1975.

History

In late 1950

Air Defense Command Aerospace Defense Command was a major command (military formation), command of the United States Air Force, responsible for air defense of the continental United States. It was activated in 1968 and disbanded in 1980. Its predecessor, Air De ...

selected the East Farmington, Wisconsin site as one of twenty-eight radar stations built as part of the second segment of the permanent radar surveillance network. Prompted by the start of the

Korean War The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...

, on July 11, 1950, the Secretary of the Air Force asked the Secretary of Defense for approval to expedite construction of the second segment of the permanent network. Receiving the Defense Secretary's approval on July 21, the Air Force directed the Corps of Engineers to proceed with construction. Construction of the station began in 1950 and was opened in June 1951. The 674th Aircraft Control and Warning Squadron was assigned and began operating a pair of AN/CPS-6B radars from the site. 261 enlisted and 33 officers were assigned, and initially the station functioned as a Ground-Control Intercept (GCI) and warning station. As a GCI station, the squadron's role was to guide interceptor aircraft toward unidentified intruders picked up on the unit's radar scopes. East Farmington was re-designated as Osceola Air Force Station on 1 December 1953. The radars were retired at the end of the decade as an AN/FPS-7 search radar and two AN/FPS-6A height-finder radars were installed during 1959. During 1959 Osceola AFS joined the

Semi Automatic Ground Environment The Semi-Automatic Ground Environment (SAGE) was a system of mainframe computer, large computers and associated computer network, networking equipment that coordinated data from many radar sites and processed it to produce a single unified image ...

(SAGE) system, initially feeding data to DC-10 at Duluth AFS, Minnesota. After joining, the squadron was re-designated as the 674th Radar Squadron (SAGE) on 15 July 1959, its direction and control duties taken over by DC-10. The radar squadron provided information 24/7 to Duluth where it was analyzed to determine range, direction altitude speed and whether or not aircraft were friendly or hostile. On 31 July 1963, Osceola was re-designated as NORAD ID Z-35. In addition, the two height-finder radars were modified to

AN/FPS-90 The AN/FPS-6 Radar was a long-range height finding radar used by the United States Air Force's Air Defense Command. The AN/FPS-6 radar was introduced into service in the late 1950s and served as the principal height-finder radar for the United S ...

sets in 1963. One of the AN/FPS-90 was retired a few years later. In addition to the main facility, Osceola operated the following AN/FPS-18 Gap Filler sites: * Northfield, MN (P-35B) * Jim Falls, WI (P-35C) * La Crescent, MN (P-35F) Over the years, the equipment at the station was upgraded or modified to improve the efficiency and accuracy of the information gathered by the radars. In November 1974 the Air Force announced that Osceola would be closing due to what was called "redundancies with more strategically located radars". The 674th Radar Squadron (SAGE) was inactivated in March 1975 as part of a draw-down of ADC, and was closed on 30 April. Today, Osceola Air Force Station is used as an Association Retreat Center. Most of the buildings are in use and well-maintained. The former radar towers are still standing.

Air Force units and assignments

Units

; 674th Radar Squadron * Constituted as the 674th Aircraft Control and Warning Squadron : Activated on 8 October 1950 : Redesignated 674th Radar Squadron (SAGE) on 15 July 1959 : Redesignated 674th Radar Squadron on 1 February 1974 : Inactivated 31 March 1975Cornett & Johnson, p. 159 Assignments *

543d Aircraft Control and Warning Group The 543d Aircraft Control and Warning Group is a disbanded United States Air Force unit. It was last assigned to the 31st Air Division, Air Defense Command, stationed at Fort Snelling, Minnesota. It was inactivated on 10 February 1952. History T ...

, 18 October 1950 *

37th Air Division The 37th Air Division (37th AD) is an inactive United States Air Force organization. Its last assignment was with Air Defense Command at Goose Air Force Base, Labrador, Canada It was inactivated on 30 June 1970. History Strategic Air Command Es ...

, 1 January 1959 *

30th Air Division The 30th Air Division (30th AD) is an inactive United States Air Force organization. Its last assignment was with Air Defense Command, assigned to Tenth Air Force, being stationed at Sioux City Air National Guard Base, Sioux City Municipal Air ...

, 1 April 1959 *

Duluth Air Defense Sector The Duluth Air Defense Sector (DUADS) is an inactive United States Air Force organization. Its last assignment was with the Air Defense Command 29th Air Division, being stationed at Duluth Airport, Minnesota. It was inactivated on 1 April 1969 ...

, 1 July 1959 *

29th Air Division The 29th Air Division (29th AD) is an inactive United States Air Force organization. Its last assignment was with Air Defense Command, being stationed at Duluth International Airport, Minnesota. It was inactivated on 15 November 1969. History ...

, 1 April 1966 *

34th Air Division The 34th Air Division (34th AD) is an inactive United States Air Force organization. Its last assignment was with Air Defense Command at Custer Air Force Station, Michigan. It was inactivated on 31 December 1969. History Assigned to Air Def ...

, 15 September 1969 * 29th Air Division, 14 November 1969 * 23d Air Division, 19 November 1969 – 31 March 1975

References

Notes

; Explanatory notes ; Citations

Bibliography