The San Francisco Conference, 25 April - 26 June 1945: The United States Sign the United Nations Charter

"Delegates of fifty nations met at San Francisco between April 25 and June 26, 1945. Working on the Dumbarton Oaks proposals, the Yalta Agreement, and amendments proposed by various Governments, the Conference agreed upon the Charter of the United Nations and the Statute of the new International Court of Justice. The Charter was passed unanimously and signed by all the representatives. It came into force on October 24, 1945, when China, France, the USSR, the United Kingdom, the United States and a majority of the other signatories had filed their instruments of ratification.
Edward Reilly Stettinius, Jr., Secretary of State, Chairman of the delegation from the United States, signing the UN Charter at a ceremony held at the Veterans' War Memorial Building on 26 June 1945. At left is President Harry S. Truman."