26°S 129°E / 26°S 129°E Today South Australia's land borders are defined to the west by the 129° east longitude (129° east) with Western Australia, to the north by the 26th parallel south latitude (26° south) with the Northern Territory and Queensland and to the east by 141° east longitude (141° east) with Queensland, New South Wales and Victoria; however, this is not where all borders are actually marked on the ground.
The South Australian boundaries are shared with the Western Australian border, the Northern Territory border, the Queensland borders, the New South Wales border and the Victorian border—that is, all states and territories except for the Australian Capital Territory and Tasmania.