Why were Iceland, Greenland, and the Faroe Islands occupied by the United States during World War II? As title

At that time, Iceland and Greenland were both Danish overseas colonies. Therefore, during World War II, Iceland naturally sided with the Allies. Germany sent U-boats to attack ships and ports in Iceland, but Iceland was far away and located in the Arctic Ocean, so Germany was somewhat beyond its reach. The Allies can use the ports of Iceland and send transport fleets to the Soviet Union to transport war supplies to it. The most famous example is the "PQ-17" ocean-going fleet.

In addition, when Denmark surrendered to Germany, it "lent" overseas colonies such as Iceland and Greenland to the United States. After World War II, the United States returned to Denmark and became independent.

About Iceland: Before the division of the United Kingdom of Denmark and Norway in 1814 according to the treaty of Kiel, Iceland was a colony of the King of Norway, and thereafter became a dependent state of Denmark. In 1874, the Danish government granted Iceland limited autonomy. In 1918, Iceland further gained independence and sovereignty similar to that of a protectorate in domestic affairs, while Denmark still retained power in foreign affairs and defense. In 1940, Germany occupied Denmark (mainland), and the United States "borrowed" Iceland in the same year. The Danish king continued to maintain legal rule until the establishment of the Republic of Iceland in 1944.

About the Faroe Islands: In 1380, it was incorporated into Denmark with Norway. In 1720, it was placed under the jurisdiction of Danish Iceland. In 1816, it was established as an overseas county. After Denmark's defeat at the beginning of World War II (1940~1945), the British army occupied the Faroe Islands. After the war, on March 30, 1948, the Faroe Islands were granted a high degree of autonomy by Denmark and became an overseas autonomous territory. In 1948 it was granted autonomy under Danish rule.