What is the Commonwealth of Australia?

The Commonwealth of Australia is the official name of the Australian nation as established by federation on 1 January 1901. The name reflects the political concept of a commonwealth: a federation of states united under a single national government but retaining individual state identities and powers. The Commonwealth is the country, not just one level of government, although the term is sometimes used colloquially to refer specifically to the federal level.

The Commonwealth was established by the Commonwealth of Australia Constitution Act 1900, an Act of the British Parliament that gave legal effect to the Constitution approved by the six Australian colonies. The name was chosen at the constitutional conventions of the 1890s, with delegates rejecting alternatives including Federation, Federated States, United Australia, and Dominion of Australia. The Commonwealth name drew on the historical use of commonwealth in English political writing (notably Cromwell's Commonwealth of the seventeenth century) to mean a state governed for the common good.

The Commonwealth is constitutionally made up of the six original states (New South Wales, Victoria, Queensland, South Australia, Western Australia, and Tasmania) and the federal government in Canberra. The two self-governing internal territories (Australian Capital Territory and Northern Territory) operate under federal supervision but are part of the Commonwealth. External territories (Christmas Island, the Cocos (Keeling) Islands, Norfolk Island, Australian Antarctic Territory, Heard Island and McDonald Islands, Ashmore and Cartier Islands, and the Coral Sea Islands Territory) are administered by the federal government but sit outside the six-state federation.

Australia is also a member of the Commonwealth of Nations (the Commonwealth, formerly the British Commonwealth), a voluntary association of 56 independent member states that share historical ties through the British Empire. The Commonwealth of Nations operates through the Commonwealth Secretariat in London, holds biennial Commonwealth Heads of Government Meetings (CHOGMs), operates the Commonwealth Games every four years, and supports shared programmes in education, health, and democracy. King Charles III is the head of the Commonwealth of Nations and is also the head of state of Australia under the same Crown.