1821 in Australia
- Monarch - George IV
- 3 February - Sir Thomas Brisbane is commissioned as Governor to succeed Macquarie. He replaces Macquarie on 1 December of the same year.
- February - John Bigge finishes gathering evidence on all aspects of the colonial government, including finances, the church, the judiciary, and the convict system. He then sails back to England.
- 1 May - The Australian Magazine, Australia's first periodical, begins publication.
- The Female Factory, for women convicts, is separated from the Parramatta Gaol. Many women are selected as brides or for domestic service.
- Parramatta Marist High School, Australia's first private school, founded by John Joseph Therry.
- Wool export in Australia - 75,400 pounds.
Exploration and settlement
- March – Port Macquarie, a penal settlement, was established for convicts that had committed secondary crimes in New South Wales.