Location and original population In 1818, Sir
John Ross's expedition made first contact with nomadic
Inughuit in the area.
James Saunders's expedition aboard
HMS North Star was marooned in
North Star Bay in 1849–50 and named landmarks. In 1910 explorer
Knud Rasmussen established a missionary and trading post there. He called the site "Thule" after classical
ultima Thule; the Inuit called it
Umanaq or
Uummannaq ("heart-shaped"), and the site is commonly called "Dundas" today. Whaling captain, explorer, and ethnologist
George Comer discovered a midden, dubbed
Comer's Midden, at Umanaq in 1916, and an archaeological excavation subsequently revealed a village of the proto-Inuit who came to be called the
Thule people. The United States abandoned its territorial claims in the area in 1917 in connection with the purchase of the
Virgin Islands. Denmark assumed control of the village in 1937. A cluster of huts known as
Pituffik ("quay, dock") stood on the wide plain where the base was built in 1951; a main base street was named Pituffik Boulevard. The population was
forcibly relocated to Thule. Later in 1953, the USAF planned to construct an air defense site near that village, and in order to limit contact with soldiers, the Danish government again relocated 130 inhabitants of "Old Thule", settling them north in a newly constructed village also named Thule (colloquially "New Thule", now
Qaanaaq). In a Danish Supreme Court judgment of 28 November 2003, the move was considered an
expropriative intervention. During the proceedings, the Danish government recognized that the movement was a serious interference and an unlawful act against the local population. The Thule tribe was awarded damages of 500,000
kroner, and the individual members of the tribe who had been exposed to the transfer were granted compensation of 15,000 or 25,000 kroner each. A Danish radio station continued to operate at Dundas, and the abandoned houses remained. The USAF used that site only for about a decade, and it has since returned to civilian use. Knud Rasmussen was the first to recognize the Pituffik Plain as ideal for an airport. USAAF Colonel
Bernt Balchen, who built
Sondrestrom Air Base, knew Rasmussen and his idea. Balchen led a flight of two
Consolidated PBY Catalina flying boats to Thule on 24 August 1942 and then sent a report advocating an air base to
USAAF chief
Henry "Hap" Arnold. However, the 1951 air base site is a few kilometers inland from the original 1946 airstrip and across the bay from the historical Thule settlement; an
ice road connects it. The joint Danish-American defense area, designated by treaty, also occupies considerable inland territory in addition to the air base itself.
World War II After the
German occupation of Denmark on 9 April 1940,
Henrik Kauffmann, Danish Ambassador to the United States, agreed "In the name of the king" with the United States, authorizing the United States to defend the Danish colonies on Greenland from German aggression. This agreement faced Kauffmann with a charge of
high treason by the
protectorate Government. Beginning in the summer of 1941, the United States Coast Guard and the War Department established weather and radio stations at
Narsarsuaq Airport (
Bluie West-1),
Sondrestrom Air Base (Bluie West-8), Ikateq (
Bluie East Two), and
Gronnedal (Bluie West-9). In 1943 the
Army Air Forces set up
weather stations
Scoresbysund (Bluie East-3) on the east coast around the southern tip of Greenland, and Thule (
Bluie West-6) to be operated by Danish personnel. Many other sites were set up, but BW-6, isolated in the far North, was then of very minor importance.
Joint weather station After liberation, Denmark ratified the Kauffmann treaty but began efforts to take over US installations. Nonetheless, in the summer of 1946, the radio and weather station was enhanced with a gravel airstrip and an upper-air (balloon) observatory. This was part of an American-Canadian initiative to construct joint weather stations in the High Arctic. This station was under joint US-Danish operation. The location changed from the Thule (Dundas) civilian village to mainland Pituffik. From 1946 to 1951, the airstrip played an important role in Arctic resupply, aerial mapping, research, and search-and-rescue. The treaty's ratification in 1951 did not change much, except that the
Danish national flag must be side by side with the
US national flag on the base.
Thule Air Base In 1949, Denmark joined the
North Atlantic Treaty Organization (NATO) and abandoned its attempt to remove the United States bases. By the outbreak of the
Korean War the next year, the USAF embarked on a global program of base-building in which Thule (at the time) would be considered the crown jewel owing to its location across the Pole from the
Soviet Union, as well as its merit of being the northernmost port to be reliably resupplied by ship. Thule became a key point in American nuclear retaliation strategy.
Strategic Air Command (SAC) bombers flying over the
Arctic presented less risk of early warning than using bases in the United Kingdom. Defensively, Thule could serve as a base for intercepting bomber attacks along the northeastern approaches to Canada and the United States. A board of Air Force officers headed by
Gordon P. Saville recommended pursuing a base at Thule in November 1950. It was subsequently supported by the
Joint Chiefs of Staff and approved by
President Truman. To replace the agreement entered into during World War II between the US and Denmark, a new agreement concerning Greenland was signed on 27 April 1951 and ratified by Denmark on 1 June 1951 (effective on 8 June 1951). At the request of NATO, the agreement became a part of the NATO defense program. The pact specified that the two nations would arrange for the use of facilities in Greenland by NATO forces in defense of the NATO area known as the Greenland Defense Area. Thule Air Base was constructed in secret under the code name
Operation Blue Jay, but the project was made public in September 1952. Construction for Thule Air Base began in 1951 and was completed in 1953. The construction of Thule is said to have been comparable in scale to the enormous effort required to build the
Panama Canal. The
United States Navy transported the bulk of men, supplies, and equipment from the naval shipyards in
Norfolk, Virginia. On 6 June 1951, an armada of 120 ships sailed from
Naval Station Norfolk. On board were 12,000 men and 300,000 tons of cargo. They arrived at Thule on 9 July 1951. Construction, aided by continuous daylight in summer, took place around the clock. The workers lived on board the ships until quarters were built. Once they moved into the quarters, the ships returned home. On 16 June 1951, the base was accidentally discovered by French cultural anthropologist and geographer
Jean Malaurie and his Inuit friend Kutikitsoq, on their way back from the geomagnetic North Pole.
Strategic Air Command , Thule Air Base, Greenland, 1955 Originally established as a Strategic Air Command installation, Thule periodically served as a dispersal base for
B-36 Peacemaker and
B-47 Stratojet aircraft during the 1950s. It also provided an ideal site to test the operability and maintainability of these weapon systems in extreme cold weather. Similar operations were also conducted with
B-52 Stratofortress aircraft in the 1950s and 1960s. In 1954, the
Globecom Tower, a tower for military radio communication, was built at Northmountain. At the time of its completion, it was the third tallest human-made structure on earth and the tallest structure north of the Arctic Circle in the Western hemisphere. In the winter of 1956–1957, three
KC-97 tankers and alternately one of two
RB-47H aircraft made polar flights to inspect Soviet defenses. Five KC-97s were prepared for flight with engines running in temperatures of to ensure three could achieve airborne status. After a two-hour head start, a B-47 would catch up with them at the northeast coastline of Greenland where two would offload fuel to top off the B-47's tanks (the third was an air spare). The B-47 would then fly seven hours of reconnaissance, while the tankers would return to Thule, refuel, and three would again fly to rendezvous with the returning B-47 at northeast Greenland. The B-47 averaged ten hours and in the air, unless unpredictable weather closed Thule. In that case, the three tankers and the B-47 had to additionally fly to one of three equidistant alternates: England,
Alaska, or
Labrador. This sometimes occurred in moonless, 24-hour
Arctic darkness, December through February. These flights demonstrated the capabilities of the US
Strategic Air Command to
Soviet Anti-Air Defense. In 1959, the airbase was the main staging point for the construction of
Camp Century, some from the base. Carved into the ice, and powered by a
nuclear reactor,
PM-2A Camp Century was officially a scientific research base, but in reality was the site of the top secret
Project Iceworm. The camp operated from 1959 until 1967. In the late 1950s, the
DEW 1 to 4 were built as "weather stations". Thule Air Base would act as a supply station for the DYE bases. Other nearby installations built at the time that received support from Thule Air Base included the
Cape Atholl (
LORAN station),
Camp TUTO (Ice Cap Approach Ramp and Airstrip), Sites 1 and 2 (Ice Cap Radar Stations),
Pingarssuit Mountain ("P Mountain") (radar and communications site),
Thule Site J (BMEWS), North and South Mountains (research sites), and a research rocket firing site. It also was essential in the construction and resupply of High Arctic weather stations, including
CFS Alert (
Alert Airport) and
Station Nord.
Aerospace defense during a visit to the base on 11 October 2021 In 1957, construction began on four
Nike Missile sites around the base, and they and their radar systems were operational by the end of 1958. In 1961, a Ballistic Missile Early Warning System (BMEWS) radar was constructed at "J-Site", northeast of the main base. BMEWS was developed by the
RCA Corporation to warn North America of a transpolar missile attack from the Russian mainland and submarine-launched missiles from the Arctic and North Atlantic oceans. At this time, Thule was at its peak, with a population of about 10,000. Starting in July 1965, activities at Thule were generally downsized. The base host unit, the
4683d Air Defense Wing, was discontinued. By January 1968, the population of Thule was down to 3,370. On 21 January 1968, a B-52G bomber carrying four nuclear weapons
crashed just outside Thule. Thule is the location where the fastest recorded sea level surface wind speed in the world was measured when a peak speed of was recorded on 8 March 1972, immediately prior to the instrument's destruction.
Air Force Space Command over Thule Air Base in 2017 Thule became an Air Force Space Command base in 1982. The US and Denmark agreed to reduce the base to half its original area on 30 September 1986. It was home to the 821st Space Base Group, which exercised air base support responsibilities within the Thule Defense Area. The base hosts the
12th Space Warning Squadron (21st Operations Group, 21st Space Wing), a Ballistic Missile Early Warning Site designed to detect and track ICBMs launched against North America. Missile warning and space surveillance information flows to NORAD command centers located at
Peterson Space Force Base,
Colorado. Thule is also host to Detachment 1 of the
23rd Space Operations Squadron, part of the
50th Space Wing's global satellite control network, as well as operating many new weapons systems. In addition, the airfield boasts a asphalt runway, with 3,000 US and international flights per year. The Dundas Peninsula, including Old Thule and Uummannaq, was relinquished by the US and returned to Danish jurisdiction on 20 February 2003. A delegation from the
NATO Parliamentary Assembly visited Thule in early September 2010 and were told by the base commander that, at that time (summer), approximately 600 personnel were serving at Thule, a mix of mostly US and Danish active duty personnel and contractors. In 2015-2016, the runway was repaved, the first time since 1991. The runway is white to reduce permafrost thawing. Previously painted white, during the re-paving, extruded polystyrene foam boards were used in 18% of the runway instead of white. There is only a brief period each year in the summer when sea ice thins sufficiently to send supply ships to the base. The US sends one heavy supply ship each summer in what is called
Operation Pacer Goose.
Pituffik Space Base In 2020, Thule Air Base was formally transferred to the
United States Space Force. On 6 April 2023, Thule was renamed Pituffik Space Base, reflecting its status as a Space Force base and the native name for the region.
Opposition to Trump Greenland threats On 28 March 2025, Vice President
JD Vance, his wife
Usha, and
Mike Waltz, the national security adviser, toured the base, as part of a trip arranged by the
Trump administration. Vance was the most senior US government official ever to visit the base. The visit came during a time of renewed discussion of the
proposed acquisition of Greenland by President
Donald Trump and was opposed by some Greenlanders. On 11 April 2025, the base commander, Colonel
Susannah Meyers, was relieved of command by the Trump administration for "undermining" Vice President Vance after his visit by sending an email to base personnel (staffed by Americans, Canadians, Danes, and Greenlanders) that included: "I spent the weekend thinking about Friday's visit [by VP Vance]the actions taken, the words spoken, and how it must have affected each of you. I do not presume to understand current politics, but what I do know is the concerns of the US administration discussed by Vice President Vance on Friday are not reflective of Pituffik Space Base. I commit that, for as long as I am lucky enough to lead this base, all of our flags will fly proudlytogether". • 662nd Air Base Squadron, 20 July 1951 • : Redesignated: 6612th Air Base Group, 1 January 1952 • : Redesignated: 6607th Air Base Wing, 1 June 19541 April 1957 •
318th Fighter Interceptor Squadron, 1 July 19535 August 1954 •
74th Fighter-Interceptor Squadron, 20 August 195425 June 1958 •
320th Air Refueling Squadron, 4 May 195510 June 1957 • : Detached from
320th Bombardment Wing,
March AFB, California •
509th Air Refueling Squadron, c. 17 June 1955c. 3 August 1955 • : Detached from
509th Bombardment Wing,
Walker AFB,
New Mexico •
96th Air Refueling Squadron, 13 July 195514 September 1955 • : Detached from
96th Bombardment Wing,
Altus AFB,
Oklahoma •
26th Air Refueling Squadron, 9 September 19552 November 1955; 5 September 195615 December 1956 • : Detached from
380th Bombardment Wing,
Plattsburgh AFB, New York •
42d Air Refueling Squadron, 2 November 195528 December 1955; 1 January 19577 March 1957 • : Detached from
42d Bombardment Wing,
Loring AFB,
Maine •
71st Air Refueling Squadron, 29 December 195527 March 1956 • : Detached from
2d Bombardment Wing,
Barksdale AFB,
Louisiana •
341st Air Refueling Squadron, 27 March 195626 June 1956 • : Detached from
341st Bombardment Wing,
Dyess AFB,
Texas •
40th Air Refueling Squadron, 27 June 19564 September 1956; c. 1 October 1958January, 9 1959 • : Detached from
40th Bombardment Wing,
Smoky Hill AFB,
Kansas •
340th Air Refueling Squadron, 29 October 195630 December 1956 • : Detached from
340th Bombardment Wing,
Whiteman AFB,
Missouri •
100th Air Refueling Squadron c. 2 Jan 19582 Apr 1958, Detached from 100th Bomb Wing Pease AFB New Hampshire •
509th Air Refueling Squadron c. 3 Apr 19584 Jul 1959, Detached from 509th Bomb Wing Pease AFB New Hampshire •
4083d Strategic Wing, 1 April 19571 July 1959 • 4083d Air Base Group, 1 April 1957 • : Redesignated: 4083d Air Base Wing, 1 July 1960 • : Redesignated: 4083d Air Base Group, 1 October 1960 • : Redesignated: 4683d Combat Support Group, 1 July 1965 • : Redesignated: 4683d Air Base Group, 1 July 19701 October 1977 •
4683d Air Defense Wing, 1 July 19601 July 1965 •
327th Fighter-Interceptor Squadron, 3 July 195825 March 1960 •
332d Fighter-Interceptor Squadron, 1 September 19601 July 1965 • OL-5, 6594th Test Wing (Satellite), Air Force Systems Command, 15 October 1961 • : Redesignated: 22nd Space Operations Squadron, 1 June 1997 • : Redesignated: Det 3, 22d Space Operations Squadron, 1 May 2004 • : Redesignated: Det 1, 23d Space Operations Squadron, 1 October 2010 – present • 12th Missile Warning Group, 31 March 1977 • : Redesignated: 12th Missile Warning Squadron, 15 June 1983 • : Redesignated: 12th Missile Warning Group, 1 October 1989 • : Redesignated: 12th Space Warning Squadron, 15 May 1992 – present • 4711th Air Base Squadron, 31 March 1977 • : Redesignated: 4685th Air Base Squadron, 1 October 198031 March 1981 • 821st Air Base Group, 1 June 2002present • : Redesignated: 821st Space Base Group, 6 April 2023
Major Army units assigned • 4th Battalion,
55th Artillery, 1 Sep 195820 Dec 1965. (
Nike) • 7th Anti-Aircraft Artillery Group, 1 July 1955 – 20 December 1965 (Redesignated 7th Artillery Group 20 March 1958) [A, B, C, and D Batteries 90mm AAA cannon; 549th 75mm AAA BN (Sky Sweeper); 51st Ordnance Company] ==Remote tracking station==