Federalism was adopted, as a constitutional principle, in Australia on 1 January 1901 – the date upon which the six self-governing Australian Colonies of New South Wales, Queensland, South Australia, Tasmania, Victoria, and Western Australia federated, formally constituting the Commonwealth of Australia. It remains a federation of those six original States under the Constitution of Australia.
Australia is the seventh oldest surviving federation in the world after the United States (1789), Mexico (1824), Switzerland (1848), Argentina (1853), Canada (1867), and Brazil (1891).