1820 in Australia
The following lists events that happened during 1820 in Australia.
Incumbents
- Monarch – George III until 29 January 1820 then George IV
Governors
Governors of the Australian colonies:- Governor of New South Wales- Major-General Lachlan Macquarie
- Lieutenant-Governor of Tasmania – Colonel William Sorell
Events
- 3 May – John Joseph Therry and Philip Conolly, the first Catholic priests officially appointed to Australia, arrive at Port Jackson from Ireland.
- 19 August – Joseph Wild discovers Lake George and names the Snowy Mountains.
- 28 October – Governor Macquarie names Lake George after King George III.
- 1 December – Campbelltown, New South Wales is established.
- Sydney has 1,084 buildings – mostly single-storey dwellings – and 12,079 people.
- Sheep population in Australia - 120,000.