US, Denmark, and Greenland sign Arctic defense pact expanding military base access

Trilateral security pact signed in New York

On Tuesday, 22 September 2026, US President Donald Trump, Danish Prime Minister Mette Frederiksen, and Greenland Prime Minister Jens-Frederik Nielsen signed a defense agreement on the sidelines of the United Nations General Assembly in New York. The ten-page document modernizes the bilateral defense pact signed by the United States and Denmark in 1951 and amended in 2004. Danish and Greenlandic delegations had arrived in New York on 20 September, two days after Trump announced that an agreement had been reached. Unlike previous defense treaties concerning the island, the new text includes the government in Nuuk as a direct signatory. The treaty has no expiration date and takes effect once parliamentary processes in Denmark and Greenland conclude.

“This is tremendous for Europe and for the United States and for everyone. And for Greenland, it is going to be incredible.”

Expanded military access and base locations

The pact expands the US military presence across the Arctic territory while maintaining existing facilities. The United States currently operates only Pituffik Space Base in northern Greenland, which focuses on early missile warning and space surveillance, down from 17 installations maintained after 1945. Under the new terms, Washington secures rights to upgrade Pituffik and establish two additional defense sites at Narsarsuaq in the south, where the United States previously ran Bluie West One until the 1950s, and at Mestersvig in the east, where the Danish military operates a patrol base. The United States gains transit rights by air, land, and sea between designated locations, alongside an expedited process for unmanned military and drone installations subject to final Danish and Greenlandic approval. Any construction of further military bases beyond these sites requires unanimous approval from all three governments.

Sovereignty and economic terms

The treaty reaffirms Danish sovereignty over Greenland while recognizing the local population's right to self-determination, ensuring the defense framework remains binding even if Greenland opts for independence. Non-NATO nations are barred from establishing military bases or maintaining permanent military forces on the island without consent from Washington, Copenhagen, and Nuuk. The agreement also restricts investments from entities based outside NATO, its partner network, or the European Union. In exchange, the text mandates commercial preferences directing defense contracts to Greenlandic enterprises and requires military operations to respect local hunting and fishing practices. The signatories also established joint counter-espionage protocols and granted the United States authority to review nearby construction projects that could compromise base security.

Shift from territorial purchase to defense terms

The signing concludes months of confidential drafting by diplomats seeking an alternative to Donald Trump's stated goal of annexing Greenland. In January, Trump argued that securing direct territorial ownership was psychologically necessary for success, comparing the potential acquisition to President Thomas Jefferson's Louisiana Purchase. Danish Prime Minister Mette Frederiksen had warned that any unilateral takeover would effectively end the NATO alliance, prompting European governments to conduct joint security drills on the island. While Trump praised the final treaty, Mikkel Runge Olesen, a researcher at the Danish Institute for International Studies, assessed that the agreement yields limited tangible gains for Washington given the diplomatic strain incurred during negotiations.

“It is an extraordinarily high price to pay for relatively limited changes.”