United Nations Security Council
The UN officially came into existence on 24 October 1945 upon ratification of the Charter by the five then-permanent members of the Security Council and by a majority of the other 46 signatories. On 17 January 1946, the Security Council met for the first time at Church House, Westminster, in London, United Kingdom.
United States National Security Council
The National Security Council was established by the National Security Act of 1947 (PL 235 – 61 Stat. 496; U.S.C. 402), amended by the National Security Act Amendments of 1949 (63 Stat. 579; 50 U.S.C. 401 et seq.). Later in 1949, as part of the Reorganization Plan, the Council was placed in the Executive Office of the President.