Trump Signs Greenland Security Deal, Expanding U.S. Military Access to the Arctic

President Trump signed a new security agreement with Denmark and Greenland on Tuesday, September 22, on the sidelines of the United Nations General Assembly in New York. The deal grants the United States wide-ranging powers to secure and defend the Arctic island, which remains Danish territory.

What the deal does

The agreement reaffirms Greenland's sovereignty as part of the Kingdom of Denmark, but gives the U.S. broad access to the island's airspace and territory. It allows the U.S. to expand the existing Pituffik Space Base, the northernmost American military installation, which serves as an early-warning system for incoming missiles. Beyond expanding Pituffik, the amended deal lets the U.S. establish two new bases and leaves the door open for additional defense areas.

The accord calls for wide U.S. military mobility on Greenland's territory, including undersea access, on the basis that the signatories share an interest in letting the U.S. military defend the NATO area, Greenland itself, and the American continent — including through Trump's planned "Golden Dome" missile defense system. Denmark's prime minister said no decision had been made yet on the specifics of that system.

The deal also sets ground rules for everyone else: no non-NATO country will be allowed to set up its own manned or unmanned military installations in Greenland, or maintain a persistent military presence there unless the signatories agree otherwise. Notably, the agreement has no end date, and if Greenland ever chooses independence, it will still remain in NATO and take on Denmark's rights and obligations under the deal.

Who signed it, and what they said

Trump, Danish Prime Minister Mette Frederiksen, and Greenland Prime Minister Jens-Frederik Nielsen attended the trilateral signing event during the 81st UN General Assembly in New York. Trump called it "tremendous for Europe and for the United States and for everybody and for Greenland," adding, "It's going to be incredible." He also said the agreement gives the U.S. "permanent control over security" in the territory.

Nielsen noted that "the world has changed a great deal since 1951," referring to the original security pact that this deal amends. Frederiksen, for her part, called it a "deal that can last forever," framing it as good for the U.S., Greenland, Denmark, and the broader NATO alliance.

The backstory

This follows months of tension over Trump's repeated statements that the U.S. needed greater control of Greenland for national security purposes. Trump had threatened to forcibly take Greenland if a satisfactory deal wasn't reached, and European nations had sent troops to the territory as tensions simmered. Trump has expressed interest in acquiring Greenland since at least 2019, and during his second term issued threats to seize the territory from Denmark, a NATO ally.

How big a change is this, really?

Here's where accounts diverge. The White House and Trump himself have framed this as a major, lasting win — permanent security control, new bases, guaranteed American presence. But independent analysis is more measured: experts say the deal appears to make relatively small changes to the underlying 1951 treaty, mainly keeping non-NATO countries out and permitting a modest increase in U.S. forces.

It's also worth noting what the deal does not do. It does not transfer ownership of Greenland to the United States, and it explicitly recognizes the sovereignty and territorial integrity of the Kingdom of Denmark along with Greenlanders' right to self-determination. So while Trump has talked for years about the U.S. simply acquiring Greenland, what got signed is a security and basing agreement, not an annexation.

What to watch next

Details on the "Golden Dome" missile defense component remain unresolved, and it's unclear exactly how many U.S. troops or how much infrastructure will actually materialize under the new bases provision. Given the gap between the administration's framing and outside analysts' read on the deal's practical scope, expect more reporting in the coming weeks on what specifically changes on the ground in Greenland.