Though it has always covered the state's entire south-east, Barker was historically a hybrid urban-rural seat that extended for some distance into the Adelaide area. Until 1949, only three seats--Adelaide, Boothby and Hindmarsh—were based primarily on the capital. For most of the first half-century after Federation, Barker included Glenelg and the Holdfast Bay area, and at times stretched as far as the western metropolitan suburbs of Keswick and Henley Beach. However, it became an entirely rural seat after parliament was expanded in the redistribution prior to the 1949 election, making this already strongly conservative seat even more so. Barker had always included Kangaroo Island and the connecting Fleurieu Peninsula until parliament was expanded in the redistribution prior to the 1984 election. Exchanged between Barker and Mayo since, Kangaroo Island and the Fleurieu Peninsula have been in Mayo since the redistribution prior to the 2004 election, where the massive redistribution of Wakefield, resulting from the abolition of Bonython, saw Barker absorb the Riverland from Wakefield.