Two new military bases in Greenland will be established by the USA at Narsarsuaq in southern Greenland and Mestersvig on the east coast under the security agreement signed by Greenland, Denmark and the USA. The expansion will add two locations to Pituffik Space Base, currently the only active American military base in Greenland.
President Donald Trump announced the plans shortly before the agreement was signed in New York. According to TV 2’s coverage of his speech at the UN General Assembly, he said work would begin immediately.
“We will immediately begin a process where we will build two large military bases,” Trump said.
The signed agreement uses more technical language. It allows the USA to establish defence areas at Narsarsuaq and Mestersvig, but says the modalities and technical details must still be mutually agreed by Greenland, Denmark and the USA.
There are therefore no published details yet on troop numbers, weapons systems, exact construction plans or the eventual size of either facility.
Where the new USA military bases in Greenland will be
The two sites have very different histories.
Narsarsuaq, in southern Greenland, was already home to a major American military base during and after the Second World War. The facility, known as Bluie West One, was established in 1941 and remained active until 1958.
As DR notes in its overview of the new agreement, the USA is therefore returning to a location where it maintained a substantial military presence more than six decades ago.
Narsarsuaq became an important staging point for aircraft crossing the North Atlantic during the Second World War and continued to have a military role during the early Cold War.
Mestersvig, by contrast, is not the reopening of a former American base. It is currently a Danish military station in eastern Greenland.
The site has buildings and an airstrip and is used by the Danish Armed Forces as a logistical stop, including for personnel and equipment supporting the Sirius Dog Sled Patrol (Slædepatruljen Sirius). DR describes the site as part of the existing Danish Arctic military network.
The new agreement will therefore bring an American defence area to a location already used by Denmark, but where there has not previously been a comparable permanent USA base.
Pituffik is the only USA base currently active
At present, the USA has one permanent military base in Greenland: Pituffik Space Base in the northwest.
Formerly known as Thule Air Base, the installation was built in the early 1950s after Denmark and the USA signed their 1951 defence agreement. It was renamed Pituffik Space Base in 2023.
The base plays a major role in missile warning and space surveillance and is the northernmost USA military installation. Its current missions are closely connected to the defence of North America and the wider NATO area.
Its scale today is much smaller than during the early Cold War. According to figures from the Danish Armed Forces cited by DR, the former Thule base accommodated as many as 10,000 soldiers and other personnel in the early 1950s.
In September 2025, the Danish Armed Forces estimated that around 600 people worked at Pituffik, including approximately 150 American military personnel, with the rest mainly civilian employees from Greenland, Denmark and the USA.
The new agreement explicitly gives the USA permission to modernise and expand its activities at Pituffik.
The USA once had several bases across Greenland
The American military presence in Greenland was considerably larger during the Second World War and the Cold War.
Alongside Thule and Narsarsuaq, the USA operated Søndre Strømfjord Air Base, at what is now Kangerlussuaq. USA diplomatic documents from the 1950s described Thule, Søndre Strømfjord and Narsarsuaq as the three American bases then operating in Greenland.
Søndre Strømfjord later became a joint USA-Danish air facility and eventually developed into what is today Kangerlussuaq Airport. USA Air Force records still describe Kangerlussuaq as the former USA-Danish Sondre Stromfjord Air Base.
There was also an American naval station at Grønnedal. The 1951 defence agreement provided for its transfer to Denmark while maintaining access for American and other NATO forces when required for the defence of Greenland and the North Atlantic.
Not all former USA facilities were conventional air or naval bases. One of the best-known Cold War projects was Camp Century, built beneath the Greenland ice sheet beginning in 1959. The USA Army described it as a military scientific research base, and it was later abandoned in 1967.
The American military network therefore once stretched across several parts of Greenland and included airfields, naval facilities, radar sites and experimental installations.
The American presence had been reduced to one defence area
That network gradually contracted after the Cold War.
By the time Denmark, Greenland and the USA signed the 2004 Igaliku Agreement, Thule Air Base was formally described as the only defence area remaining in Greenland.
The agreement reflected both the reduction in American military activity and Greenland’s changing political status. It also established stronger consultation mechanisms with Greenland’s Home Rule Government.
The 2026 agreement reverses that long-term geographical contraction. Once Narsarsuaq and Mestersvig are established, the USA will have designated defence locations in northwestern, southern and eastern Greenland.
More military sites could be created later
The expansion may not stop at the two new bases.
The new agreement says additional defence areas can be proposed when considered necessary for the defence of Greenland, the North Atlantic Treaty area or the American continent.
A proposal must identify the location, size, scope and intended activities. The parties must then negotiate the implementation through the Permanent Committee, and the final arrangements require mutual agreement.
Requests to establish unmanned military installations outside the defence areas will also be handled through accelerated government approval procedures.
This means that Narsarsuaq and Mestersvig are the only additional locations explicitly authorised in the agreement, but they are not necessarily the final possible expansion of the American military presence.
Greenlandic companies could benefit from construction
The agreement also contains provisions on who should benefit economically from the new military infrastructure.
The USA must award contracts for construction, maintenance and services connected with defence areas to Greenlandic suppliers to the maximum extent possible, taking into account whether local companies have the capacity to carry out the work.
The provision could make the construction of the new bases significant not only for Arctic defence but also for the Greenlandic economy.
For now, however, the most important details remain unknown. Trump has described the planned facilities as two large military bases, but the agreement itself does not define their final size.
What is already clear is the broader historical change. After decades in which the American military network in Greenland contracted until only Pituffik remained, the USA is preparing to return to Narsarsuaq, establish a new presence at Mestersvig and expand Pituffik, creating its largest geographical military footprint on the island in decades.
