The arid north is delineated from the more fertile southeast by Goyder's Line, first surveyed in the 1860s, and which has proven to be a remarkably accurate northern boundary marking where sustainable agriculture can be carried out.
East of the Mount Lofty Ranges, the Murray River flows west from New South Wales and Victoria, then south adjacent to the ranges.
Climate
The state's mean temperature range is 29°C in January and 15°C in July. Daily temperatures in parts of the state in January & February can be up to 48°C.
Highest maximum temperature: 50.7°C (123.3°F), Oodnadatta, 2 January1960 (The highest official temperature recorded in the whole of Australia).
^ Most Australians describe the body of water south of the continent as the Southern Ocean, rather than the Indian Ocean as officially defined by the International Hydrographic Organization (IHO). In 2000, a vote of IHO member nations defined the term "Southern Ocean" as applying only to the waters between Antarctica and 60 degrees south latitude.