Flag Adopted: 22 July 1870
Flag Proportion: 1:2
Use: State Ensign
South Australia became Australia′s fourth colony when it formally separated from New South Wales on 28 December 1836.
South Australia′s first flag dates from 1870 to 1876, and was a British Blue Ensign defaced with a black disc on the fly, on which the Southern Cross and the two pointers (Alpha and Beta Centauri) appeared.
The original proposal for the South Australian badge did not include the black disc. The only difference between this proposal and the badge of Victoria (at the time) was the inclusion of the pointer stars.
The Colonial Office requested that the badge be altered to make it more distinctive and less likely to be confused with that of Victoria. The British Admiralty simply suggested in July 1870 that the stars be placed "upon a black escutcheon".
The Governor of South Australia seemingly flew a slightly different flag – without the two pointers. However, historical details are sketchy as the drawings submitted to the British Admiralty have never been recovered. Only written descriptions of the designs have been found.
References
Crux Australis
Anthony Burton (Editor), Flag Society of Australia, Melbourne, Australia.
– Australian State Flags (1865-1904): A British Admiralty Legacy", Ralph Kelly, Volume VIII No 4 October 1992.
Flags of Australia (chart)
John C Vaughan, Standard Publishing House, Sydney, 1983.
Flags of the Nations (chart)
Flag Society of Australia, Flag Research Center, and National Australia Bank, Australia, 1992.