1866 in Australia

Incumbents

Governors

• Governor of New South Wales – Sir John Young, Bt
• Governor of Queensland – Sir George Bowen
• Governor of South Australia – Sir Dominick Daly
• Governor of Tasmania – Colonel Thomas Browne
• Governor of Victoria – Sir Charles Darling, then Sir John Manners-Sutton

  Premiers

• Premier of New South Wales – Charles Cowper, then James Martin
• Premier of Queensland – Robert Herbert, then Arthur Macalister, then Robert Herbert then Arthur Macalister
• Premier of South Australia – John Hart, Sr, then James Boucaut
• Premier of Tasmania – James Whyte, then Sir Richard Dry
• Premier of Victoria – James McCulloch

  Events

• 1 February – Arthur Macalister becomes Premier of Queensland
• 19 March – Sister Mary MacKillop founds the Sisters of St Joseph of the Sacred Heart at Penola, South Australia.
• 17 April – The Tariff Bill passes through the Parliament of Victoria; Australia's first protective tariffs become law the following day.
• 20 June – Adelaide's town Hall opens
• 12 July – SS Cawarra was wrecked off Newcastle, only 1 of 61 passengers and crew survive
• 18 July – The passenger vessel Netherby is wrecked off King Island, all 450 on board survived
• 20 July – Arthur Macalister resigns as Premier of Queensland during a bank crisis, he resumes his post on 7 August as the crisis eased
• 15 August – John Manners-Sutton becomes Governor of Victoria
• 8 September – The Blood or bread riots begin as unemployed men attempt to storm government stores; the riots continue to the 10th
• 10 October – Dandenong Market opens in South-East Melbourne.
• 24 October – The Intercolonial Exhibition of Australasia opens in Melbourne.
• 24 November – Richard Dry becomes Premier of Tasmania
• 7 December – John Granville Grenfell, gold commissioner, killed by bushrangers near Narromine

  Births

• 26 March – Bancroft Boake, songwriter
• 11 April – Bernard O'Dowd, writer
• 5 August – Harry Trott, cricketer

  Deaths

• 11 January – Gustavus Vaughan Brooke, Irish actor
• 3 February – William Haines, Premier of Victoria
• 7 May - Edward Charles Close, New South Wales colonial magistrate
• 5 June – John McDouall Stuart, explorer
• 25 September - Osmond Gilles, South Australian colonial treasurer