Key Details Still Unresolved as US Expands Greenland Military Defense Sites

A new agreement with Denmark and Greenland gives the United States a path to two additional military sites, wider access across the Arctic island and an expanded role for its only existing base. But key questions remain unanswered.

The deal, signed Sept. 22, preserves Danish sovereignty and Greenlanders’ right to decide their political future. It will take effect only after Denmark and Greenland complete the required parliamentary procedures.

President Donald Trump described the agreement as giving Washington permanent control over Greenland’s security. The published text grants specified military access and requires mutual agreement on details of additional defense areas.

Danish Prime Minister Mette Frederiksen called it “a deal that [could] last forever,” while Greenland Prime Minister Jens-Frederik Nielsen said it “strengthens our shared security.”

The written provisions will govern what happens when the governments choose sites, missions and spending.

What the Pentagon Gains

The agreement allows the United States to modernize and expand activities at Pituffik Space Base and establish defense areas at Narsarsuaq in southern Greenland and Mestersvig. Technical details for those two sites remain to be negotiated.

Further bases require a proposal specifying location, size, activities and mitigation measures, followed by consultations to reach mutual agreement. An unresolved proposal moves to senior officials after 90 days.

Requests for unmanned installations outside defense areas receive an accelerated review, not automatic approval.

Pituffik already serves a direct U.S. homeland defense mission. Its upgraded radar supplies ballistic missile warning and space surveillance, while a satellite control station, supports military space operations.

Military.com reported when the installation was renamed in 2023 that it supports missile warning, defense and surveillance.

The new agreement mentions a possible Golden Dome defense system but provides no design, construction schedule or cost for a Greenland component.

Narsarsuaq hosted a U.S. airfield during World War II and the early Cold War. Mestersvig is used by Denmark’s Sirius Dog Sled Patrol.

A southern airfield and an eastern outpost could give American forces more options for Arctic surveillance, movement and support, although the agreement assigns neither site a specific mission.

U.S. aircraft may fly over and land across Greenland, and public vessels receive undersea access in territorial waters—subject to any restrictions the parties mutually agree upon.

Forces may move between defense areas by land, sea and air. The text requires respect for Greenlandic hunting, fishing and other activities to the greatest extent possible. It directs U.S. contracting toward Greenlandic firms when feasible, potentially giving local communities an economic stake in construction and maintenance.

Limits on ‘Permanent Control’

Naaja Nathanielsen, a Greenlandic lawmaker in Denmark’s parliament, said she viewed participation in a binding agreement as a significant advance for Greenland’s autonomy, even though Denmark retains responsibility for defense and foreign affairs.

During a January dispute, Denmark had already said U.S. bases could expand under existing arrangements while rejecting a transfer of sovereignty. The distinction remains central to the new agreement: it broadens American military access while leaving Greenland within the Kingdom of Denmark.

The agreement has no expiration date and can be amended only by mutual consent. If Greenland becomes independent, the agreement says Denmark and Greenland must ensure that the new state assumes the existing defense arrangements and agrees to remain in NATO, applying for membership if necessary.

That promise does not itself admit an independent Greenland to NATO. The alliance’s treaty requires unanimous agreement to invite a new member. Greenland’s self-government law also requires a negotiated independence agreement, approval by its legislature and voters, as well as by Denmark’s parliament.

The pact bars non-NATO states from maintaining military installations or a persistent troop presence unless the three parties agree otherwise. It also restricts threatening control, influence or access to sensitive information in sectors such as infrastructure and mineral extraction by investors from outside NATO, NATO partner countries and the European Union.

Greenland will apply those restrictions through its investment screening laws in consultation with Denmark. The arrangement does not give Washington ownership of Greenland’s minerals or an unrestricted veto over all foreign business.

The agreement, however, offers U.S. commanders more places to operate and a stronger legal basis for access if Greenland’s status changes.

Parliamentary approval, base plans, funding and local consent will determine how much military capability follows the signing.