In January 2026, US President Donald Trump again said that the United States should own Greenland so the island could not be taken by Russia or China. The remark revived interest in events from nearly a century ago, when the world’s largest island had already become a point of rivalry among major powers.
After Germany occupied Denmark on April 9, 1940, Greenland was effectively left to fend for itself. Formally, it remained under the Danish crown, but the local administration refused to recognize collaborationist authority and began looking to the United States. Arctic weather data became critically important: they affected convoys, submarine operations and air missions. Danish journalist Peter Harmsen wrote that the Germans called Greenland Europe’s “weather kitchen.”
For Washington, the island mattered not only strategically. In southern Greenland, the mine at Ivittuut produced 95% of the world’s cryolite during the war, a mineral needed for aluminum smelting. From 1941 to 1945, the Allies shipped 20,000 tons of it out of Greenland.
On April 9, 1941, Danish envoy in Washington Henrik Kauffmann signed the Agreement relating to the Defense of Greenland with US Secretary of State Cordell Hull. After that, the American military presence on the island expanded rapidly. By the end of the war, about 6,000 personnel were stationed at the Blue West One base in Narsarsuaq alone.
At the same time, a covert struggle unfolded along the sparsely populated eastern coast against German weather stations. The Northeast Greenland Sledge Patrol was formed to patrol the area, bringing together Danes, Norwegians and Indigenous Greenlanders. In March 1943, the patrol discovered the German station Holzauge on Sabine Island. After that, Governor Eske Brun formally granted the unit the status of Greenland’s army.
The Germans soon attacked and burned the patrol’s base. During those events, Danish corporal Eli Knudsen was killed, the first and only Greenland-related combat loss of the island in World War II. Later, Marius Jensen managed to disarm German officer Hermann Ritter and, after a 290-mile trek, delivered him to the Americans. In May 1943, US aircraft destroyed Holzauge, and in April 1944 the patrol attacked the Bassgeiger station on Shannon Island, forcing the Germans to evacuate.
After the war, the unit was disbanded, but it was reestablished in 1950. Over time it received its current name, the Sirius Patrol, and it continues to serve within the Royal Danish Navy. Today, the United States maintains one military site on the island, the Pituffik Space Base, formerly Thule Air Base.