The charter of the United Nations was drawn up in San Francisco. San Francisco is a city in California, USA. The United Nations (UN) is an international organization founded in 1945 to promote peace, security, and cooperation among nations. The charter of the UN is a legal document that outlines the organization's structure, functions, and powers. It was signed on June 26, 1945, in San Francisco by representatives of 50 countries, and it came into effect on October 24, 1945, after it was ratified by the required number of member states.