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.

Births

 * 14 May – James Martin (died 1886), Premier of New South Wales