Electoral districts of South Australia

Since 1970, the South Australian House of Assembly (the "lower house") has consisted of 47 single-member electoral districts consisting of approximately the same number of enrolled voters. The district boundaries are regulated by the State Electoral Office, according to the requirements of the South Australian Constitution and are subject to mandatory redistributions by the State Electoral Office in order to respond to changing demographics.

Boundary adjustments

Electoral boundaries are adjusted after each election. The primary consideration is to attempt to ensure that the party that obtains 50% or more of the overall vote at a general election is able to form a government. The number of electors in each district must be within 10% of the average at the time of the redistribution order. After these primary considerations, other issues are considered, including economic, social and regional communities of interest.^[1] Despite this elaborate and expensive process, the system is not particularly reliable; cases where the party forming government has received less than 50% of the two-party-preferred vote are not un-common, and have occurred in three of the last four elections.

Election	1970	1973	1975	1977	1979	1982	1985	1989	1993	1997	2002	2006	2010	2014
Govt	ALP	ALP	ALP	ALP	Lib	ALP	ALP	ALP	Lib	Lib	ALP	ALP	ALP	ALP
# of seats	27	26	23	27	24	24	27	22	37	23	23	28	26	23
% of seats	57.4	55.3	48.9	57.4	51.1	51.1	57.4	46.8	78.7	48.9	48.9	59.6	55.3	48.9
% of vote	53.3	54.5	49.2	53.4	55.0	50.9	53.2	48.1	61.0	51.5	49.1	56.8	48.4	47.0

While South Australia's total population is 1.7 million, Adelaide's population is 1.3 million − uniquely highly-centralised, over 75% of the state's population resides in the metropolitan area and has 72% of seats (34 of 47) alongside a lack of comparatively-sized rural population centres, therefore the metropolitan area tends to decide election outcomes. At the 2014 election for example, although the state-wide two-party vote (2PP) was 47.0% Labor v 53.0% Liberal, the metropolitan area recorded a 2PP of 51.5% Labor v 48.5% Liberal.^[2]

List of the current 47 electoral districts

Maps

Map of rural electoral districts showing results from the 2014 election and changes since.

Map of metropolitan electoral districts showing results from the 2014 election and changes since.

Numbers of Electorates and Members

Since 1938, the South Australian House of Assembly has had single-member electoral districts. From 1938-1968 there were 39 districts. Since 1970 there have been 47 electoral districts. From 1857-1933, the number of districts varied between 12 (1912–1915) and 27 (1890–1901). Each district returned from 1-6 members.

Parliaments	Years elected	Districts	Members
1, 2	1857, 1860	17	36
3, 4, 5, 6, 7	1862, 1865, 1868, 1870, 1871	18	36
8, 9, 10	1875, 1878, 1881	22	46
11, 12	1884, 1887	26	52
13, 14, 15, 16	1890, 1893, 1896, 1899	27	54
17, 18, 19, 20	1902, 1905, 1906, 1910	13	42
21	1912	12	40
22, 23, 24, 25, 26, 27, 28	1915, 1918, 1921, 1924, 1927, 1930, 1933	19	46
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39	1938, 1941, 1944, 1947, 1950, 1953, 1956, 1959, 1962, 1965, 1968	39	39
40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53	1970, 1973, 1975, 1977, 1979, 1982, 1985, 1989, 1993, 1997, 2002, 2006, 2010, 2014	47	47