Plateau Station was the highest and most remote scientific station established by the United States. Construction of the site, started on December 13, 1965, and the first Traverse Team (named SPQML II) arrived in early 1966. The station was located at 79° 15’ South, 40° 30’ East in the far interior of the Antarctic ice cap, 11,890 feet above sea level.
Plateau Station was operated and staffed by the National Science Foundation and US Navy.
A select Team of four scientists and four navy personnel were on constant duty at the station, which was under the command of a naval medical doctor. Originally designed for two years of service, the Base was in continuous use for three years until January 29, 1969, 
when it was closed but mothballed for future use. Plateau Station was also the coldest of any United States Stations on the Continent and the site for the world’s coldest measured average temperature for a month at that time, recorded in July 1968, at −99.8 °F (−73.2 °C).
Plateau Station closed permanently in January, 1969.
Actually Plateau Station is an inactive American research and support Base on the central Antarctic Plateau.
On 22 December 2007, the Norwegian-US Scientific Traverse of East Antarctica visited the Base and entered the buildings, finding that it was mostly intact.
In 2017, the CoFi-Expedition made a stop at Plateau Station. They entered the Station through a hatch at the top of highest building, the watch tower. The Bse is completely snowbound nowadays. The only visible building at the base is the meteorological tower. The expedition left the base with the same general impression as the expedition in 2007 did.
Researcher Sepp Kipfstuhl said: «If someone should visit the base in 10 or even 20 years, it’ll have barely changed. The meteorological tower should be visible for the next 500 years».
To get something more about Plateau Station, go to:
Memoirs & Diaries — The Antarctican Society
To read a recollection of the U.S. Navy person in charge of mothballing the station, Electronics Technician John Wright, click the red link below:
John+Wright+Recollection
Ham radio Callsign issued at the time for Plateau Station was KC4USJ.
The QSL of KC4USJ here aside, prove the Hamradio activity 1968-69 from Plateau Station (WAP USA-13).
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TNX Bob Hines K4MZU for having shared this very rare QSL with us!