The United States Mission to the United Nations is located in temporary quarters at 140 East 45th Street (between Third and Lexington Avenues) while permanent offices are being re-built across the street from United Nations Headquarters. From this building the United States delegation to the United Nations, along with a staff of more than 100 persons, carries out our nation's participation in the world body. Almost all United Nations member nations maintain missions in New York City.

The term "United Nations" was suggested by Franklin D. Roosevelt and Winston Churchill during World War II, to refer to the Allies. It appeared in the Declaration by the United Nations where, on January 1, 1942, 26 nations pledged to continue fighting the Axis powers.

In 1945, representatives from 50 countries met in San Francisco for the United Nations Conference on International Organization. They deliberated on proposals that had been drafted by representatives of the Republic of China, the Soviet Union, the United Kingdom and the United States at the Dumbarton Oaks Conference between August and October of 1944. The United Nations officially came into existence on October 24, 1945, when the Charter was ratified by the Republic of China, France, the Soviet Union, the United Kingdom, the United States as well as a majority of other signatories.

In 1947 the United States Mission was created by the United Nations Participation Act to assist the President and the Department of State in conducting United States policy at the United Nations.