The first government in South Australia was quite different to what we have today. Governing power over the new British colony was divided between a board of four men and the Governor. This council met regularly in the Sitting Room of Government House. In 1842, a British Act of Parliament was passed that saw the board increased to seven. It was then decided that the public should be able to attend the council meetings. A new single brick room was built onto the Magistrates Office on North Terrace.
In 1850 The Australian Colonies Government Act passed. This led to a significant restructuring of South Australia's governing system, including a new upper house or Legislative Council. A new council chamber for the 24 members was needed.
A design competition was announced. A new building was to be constructed in Victoria Square, at the site of the present day Supreme Court. Work began on architect William Bennett Hays' winning design in 1854. However, plans were delayed due to a shortage of labour, with many South Australian men leaving for the Victorian goldfields. In the meantime, a Select Committee recommended that instead of a new building in Victoria Square, additions be made to the existing site on North Terrace.
The new Elizabethan-style chamber and ten rooms were completed by 1855. The brand new chamber quickly showed the deficiencies of the older one. Over the next two years extensions were added to the northern and western sides of the building. With both chambers complete, the new Parliament officially opened in April 1857. Ironically, the Lower House chamber was upstairs, while the Upper House chamber was downstairs!
Despite the additional space, the members were still not happy with their Parliament. However, due to costs, proposed plans for a new building over the next few year were rejected. In 1872, the House of Assembly increase with ten new members. At this time architect E.J. Woods was commissioned to oversee further additions to the building.
By 1877 work finally began on the new Parliament House. After much delay and some controversy, the House of Assembly moved into the new building on 5 June 1889. A bridge, now demolished, connected the new building to the old. The Legislative Council remained in the older building until the completion of the east wing in 1939.
There was much debate over what to do with Old Parliament House once both the House of Assembly and the Legislative Council moved into the new parliament. Many believed it should be demolished, while others argued for preservation. Plans for its demolition were stopped when the Second World War began. It was instead used as the office for wartime services.
After the war, Old Parliament House was occupied by a number of organisations and government departments. In 1976, Premier Don Dunstan announced the establishment of a museum of political and social history in the building. The first political museum in Australia opened in August 1980 and operated until 1995.
Since then, Old Parliament House has again become part of the State's parliamentary activities, serving as office and meeting space for Parliament.