When was the United Nations established?

The term "United Nations" was first used officially during World War II, on 1 January 1942, when 26 states joined in the Declaration by the "United Nations", pledging themselves to continue their joint war effort and not to seek peace as separate entities.

Towards the end of the war, USA President Franklin D Roosevelt, British Prime Minister Winston Churchill, and Soviet Premier Joseph Stalin initiated a conference to take place in April 1945. Its purpose was to plan the charter of an organisation to promote peace, security, and economic development. Nations which had agreed to the original 1942 declaration, declaring war on Germany or Japan by 1 March 1945, were called to the founding conference held in San Francisco, to draft the UN charter. The conference was attended by representatives of fifty nations.

The UN charter was signed on June 26 and ratified by the required number of states on 24 October 1945.