Editing 1951 (section)

===September===
* [[September 1]] – The United States, Australia and New Zealand all sign a mutual defense pact, the [[ANZUS Treaty]].
* [[September 2]] – The [[Sri Lanka Freedom Party]] is founded by [[S. W. R. D. Bandaranaike]].
* [[September 8]]
** [[Treaty of San Francisco]]: In [[San Francisco]], 48 representatives out of 51 attending sign a [[peace treaty]] with Japan, formally ending the [[Pacific War]]; the delegations of the [[Soviet Union]], [[Poland]] and [[Czechoslovakia]] do not sign the treaty, instead favoring separate treaties.
** The [[Security Treaty Between the United States and Japan|U.S.-Japan Security Treaty]], which allows [[United States Forces Japan|United States Armed Forces]] to be stationed in Japan even after the end of the [[occupation of Japan]], is signed by Japan and the United States.
* [[September 9]] – Chinese Communist forces move into Lhasa, the capital of Tibet.
* [[September 10]] – The United Kingdom begins an economic boycott of [[Iran]].
* [[September 20]] – [[NATO]] accepts Greece and Turkey as members.
* [[September 26]]–[[September 28|28]] – A blue sun is seen over Europe: the effect is due to ash coming from the Canadian forest fires 4 months previously.
* [[September 30]] – [[Charlotte Whitton]] becomes mayor of [[Ottawa]] and Canada's first woman mayor of a major city.