A Guide to the United States’ History of Recognition, Diplomatic, and Consular Relations, by Country, since 1776: Iceland
Following the April 9, 1940, German occupation of Denmark, Iceland took control of its own foreign relations. In July and December of that year Icelandic officials asked the United States to place Iceland under U.S. protection in accordance with the Monroe Doctrine to forestall a feared German invasion of the island. The United States was initially unenthusiastic about this proposal, but ultimately concluded that Icelandic occupation was a matter of national defense and occupied Iceland on July 7, 1941.
U.S. Recognition of Icelandic Independence, 1944.
When German forces occupied Denmark in 1940, Iceland assumed control over its own foreign affairs and gradually moved toward complete independence from Denmark. Following a plebiscite, Iceland formally became an independent republic on June 17, 1944. That same day, the United States recognized Iceland in public statements of congratulation by President Franklin D. Roosevelt and Secretary of State Cordell Hull.
Establishment of Diplomatic Relations and the American Legation in Iceland, 1941.
Diplomatic relations and the American Legation at Reykjavik were established on September 30, 1941, when Envoy Extraordinary and Minister Plenipotentiary Lincoln MacVeagh presented credentials and elevated the American Consulate to Legation status. Iceland had taken over full control of its foreign relations on April 10, 1940, although the country had not yet declared itself independent from Denmark, which was then under German occupation.