US to Expand Military Footprint in Greenland Under New Trilateral Deal

The United States is poised to significantly expand its military presence in Greenland under a trilateral agreement to be signed at the United Nations General Assembly in New York on Tuesday. President Donald Trump, Danish Prime Minister Mette Frederiksen and Greenland Prime Minister Jens-Frederik Nielsen are expected to formalise the arrangement, which would grant Washington access to two new sites alongside the existing Pituffik Space Base.

From purchase ambition to security pact

Trump's interest in Greenland dates back to his first term, when he floated the idea of purchasing the territory in 2019. The issue returned with renewed intensity after his re-election. In December 2024, he described ownership and control of Greenland as an "absolute necessity". In January 2025, he declined to rule out military force to obtain the island, triggering a diplomatic crisis with Denmark and unease among NATO allies.

Greenland's leaders repeatedly rejected the idea of becoming part of the United States, and Denmark insisted the territory was not for sale. Negotiations eventually shifted from the question of ownership to who bears responsibility for Greenland's security — a shift that produced the agreement now due to be signed.

What the deal covers

The most immediate change is expected to be a substantial expansion of America's military footprint. Under the arrangement, the US is expected to establish facilities at Narsarsuaq in southern Greenland — a former Cold War airbase closed in the 1950s, whose local population has since dwindled to a few dozen — and at Mestersvig on the east coast, an outpost currently used by Denmark's Sirius Dog Sled Patrol.

These would join Pituffik Space Base in northwestern Greenland, which supports missile-warning and space-surveillance operations. The expansion would represent the largest increase in US military infrastructure on the island since the Cold War, when Washington maintained 17 installations and more than 10,000 personnel there. Today, Pituffik is the principal US installation, with roughly 150 American personnel.

Competing interpretations

Trump has said the agreement gives the US "permanent control over security, and all other needs, in Greenland", adding that adversaries would not be allowed to establish bases, maintain forces or make sensitive investments on the island without Washington's approval.

Copenhagen, however, says the arrangement respects Danish sovereignty and Greenland's right to self-determination. Danish Foreign Minister Lars Løkke Rasmussen has said Arctic security will be placed under NATO's collective responsibility rather than left solely to the US and Denmark. Greenland's Prime Minister Jens-Frederik Nielsen has similarly said the arrangement recognises Greenland's interests and its right to self-determination.

The legal meaning of the US security commitment therefore remains one of the most important unanswered questions. The full text has not been made public, and it is unclear whether the arrangement changes the existing 1951 US-Denmark defence framework or creates a new legal structure.

Why Greenland matters

The world's largest island sits between North America and Europe, at the intersection of the Arctic and North Atlantic. Its location makes it strategically important for monitoring activity across both regions, and it holds substantial mineral and energy resources — factors gaining weight as Arctic ice retreats and competition for resources and shipping routes intensifies.

Trump has repeatedly cited concerns about Russia and China gaining a foothold in Greenland. His administration says the agreement will prevent geopolitical rivals from establishing military bases or deploying troops on the island, and seeks mechanisms to restrict sensitive investments. China's growing interest in Arctic resources has particularly concerned US officials.