Finley Air Force Station

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Finley Air Force Station (1952-1979) - A Cold War Air Force Radar Station first established in 1952 near Finley, Steele County, North Dakota. Named Finley Air Force Station after the location. Initially assigned a Permanent ID of P-29, later a Sage ID of Z-29 and a JSS ID of J-75. Abandoned in 1979.

Finley AFS Remaining Buildings Including Operations and FPS-35 Tower.


Established in 1952 and became operational in April 1952 as Finley Air Force Station manned by the 785th AC&W Squadron. The station initially had both a Ground-Control Intercept (GCI) and early warning mission. The early warning mission involved tracking and identifying all aircraft entering their airspace while the GCI mission involved guiding Air Force interceptors to any identified enemy aircraft. Controllers at the station vectored fighter aircraft at the correct course and speed to intercept enemy aircraft using voice commands via ground-to-air radio.

Initial equipment included the FPS-3 search radar and an FPS-5 height-finder radar.

SAGE System Transition

The transition of the manual GCI system to the automated SAGE system began with the installation of the FST-2 coordinate data transmitter and search radar upgrades. The FST-2 equipment digitized the radar returns and transmitted the digital returns to the SAGE direction center. Under the SAGE System, interceptor aircraft were directed to their targets by the direction center computers and controllers, greatly reducing the need for local controllers and equipment at every radar station.

The FST-2 was a very large digital system using vacuum tube technology. Over 6900 vacuum tubes were used in each FST-2 requiring 21 air-conditioned cabinets, 40 tons of air conditioning, 43.5 kva of prime power, and usually a large new addition to the operations building. The FST-2B modification added two more cabinets but with newer solid-state (transistor) technology to process coded responses from aircraft transponders.

SAGE System Operation

The site began operation as a SAGE site in April 1959 initially feeding the Grand Forks SAGE Direction Center DC-11. The search radar was upgraded to an FPS-20 and a second FPS-6 height-finder radar was installed in 1959. In 1962 an FPS-35 search radar replaced the FPS-20 and one of the FPS-6 height-finders was upgraded to an FPS-90. The remaining FPS-6 was later removed.

With the closure of the Grand Forks SAGE Direction Center DC-11 in 1963, SAGE control of Finley AFS switched to Duluth SAGE Direction Center DC-10 on 4 Sep 1963. Another realignment of sectors took place in 1969 and SAGE control of Finley AFS switched to Malmstrom SAGE Direction Center DC-20 on 15 Sep 1969 and remained there until the site closed in 1979.

In the early 1970s, the vacuum tube FST-2 Coordinate Data Transmitter was replaced with the solid state FYQ-47 Common Digitizer.

Gap Fillers

Finley AFS was responsible for the maintenance of four remote unattended gap-filler radar sites. The unattended gap filler sites were placed in locations where the main search radar lacked coverage. These sites were equipped with short range FPS-14 or FPS-18 search radars and FST-1 Coordinate Data transmitters that sent digitized radar target data to a SAGE direction center and to the main radar site. Both the radar set and the FST-1 were dual channel to increase site up time. Maintenance teams were dispatched for regularly scheduled maintenance or when fault indicators on the FSW-1 remote monitoring equipment suggested the site had problems. The FSW-1 also allowed remote operation of specific functions such as channel changes for the radar and for the FST-1, it also allowed remote operation of the diesel generators at the gap filler site. The Finley AFS gap-filler radars were located at Sheyenne, Grafton and Valley City in North Dakota and Middle River in Minnesota.

Finley AFS Gap Filler Radar Sites (edit list)
ADC NORAD Location State Type From To GPS Notes
P-29A Z-29A Sheyenne ND FPS-14, FST-1 1957-11 1968-06 47.82792,
Building shell exists
P-29B Z-29B Grafton ND FPS-14, FST-1 1957-11 1968-06 48.41198,
Building exists
P-29C Z-29C Valley City ND FPS-18, FST-1 1959-12 1967-12 46.84794,
Building exists
P-29D Z-29D Middle River MN FPS-18, FST-1 1959-04 1964-06 48.53609,
Building & tower exist


Finley AFS and the 785th were deactivated on 30 Dec 1979. There is some evidence that there was an interim period of operation at the site after that point using FAA and USAF resources until the FAA completed the nearby Finley FAA Radar Site at the old location of the Finley AFS GATR site. That operation may have lasted until 1982.

Physical Plant

Finley AFS GATR Site.

The physical plant of the site was divided into the main site, a cantonment area, a housing area and a radio site. The main site housed the operations buildings, the radar towers, and the backup generators. The adjacent cantonment area housed the enlisted barracks, the bachelor officer's quarters, the orderly room, the dining hall, the motor pool and other support buildings. Apart from the main site were two housing areas for married personnel. A separate Ground to Air Transmitter/Receiver (GATR) radio site housed the radio equipment for directing aircraft intercepts under the SAGE System.

Finley AFS Major Equipment List
Search Radar HF Radar Data Systems
Unit Designations
  • 785th Aircraft Control & Warning (AC&W) Squadron (1952-1960)
  • 785th Radar Squadron (SAGE) (1960-1979)
785th Assignments
  • 10 Apr 1951 - Activated at Finley AFS, ND, assigned to 543rd AC&W Gp.
  • 6 Feb 1952 - Transferred to 31st AD.
  • 16 Feb 1953 - Transferred to 29th AD.
  • 1 Mar 1956 - Transferred to 31st AD.
  • 1 Jan 1959 - Transferred to 29th AD.
  • Apr 1959 - Transferred to Grand Forks ADS ca. (Grand Forks)
  • 15 Jan 1960 - Redesignated from AC&W Sq to 785th Radar Sq (SAGE).
  • 4 Sep 1963 - Transferred to Duluth ADS. (Duluth)
  • 1 Apr 1966 - Transferred to 29th AD. (Duluth)
  • 15 Sep 1969 - Reassigned to 28th AD. (Malmstrom)
  • 19 Nov 1969 - Reassigned to 24th AD. (Malmstrom)
  • Nov 1979 - Reassigned to TAC (ADTAC) (Malmstrom)
  • 30 Dec 1979 - Deactivated.

Finley Air Force Station Partial Commanders List (edit list)
Assumed Relieved Rank Name Cullum Notes
1969~ 1971~ Lt. Colonel Pruit, William J. N/A
1972~ 1974~ Major Pennefather, Michael N/A

Current Status

FPS-35 Tower and Ops Building with the Back Torn Down

Abandoned and used as a land fill by the city of Finley in Steele County, North Dakota. The FPS-35 tower is still standing. The operations building is still standing but with one wall knocked down. A couple of other main site buildings remain. The housing areas have both been leveled. The GATR site building is still in place next to the Finley FAA Radar Site.

Location: Near Finley in Steele County, North Dakota. Zoom out on the map to see the GATR site.

Maps & Images

Lat: 47.51583 Long: -97.86861

  • Multi Maps from ACME
  • Maps from Bing
  • Maps from Google
  • Elevation: 1558'

See Also:


  • Cornett, Lloyd H. & Johnson, Mildred W., A Handbook of Aerospace Defense Organization (1946-1980), Office of History ADC, Peterson AFB, Colorado, 31 Dec 1980, 179 pages, Pdf, page 169.
  • Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf, page 145.
  • USGS Geographic Names Information System (GNIS) Database Entry: 2087612


Visited: 5 Aug 2016

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