This article is about a drainage division; for other uses, see Southwest, Western Australia.

The South-west Corner of Western Australia is one of the only two temperate and relatively fertile parts of mainland Australia. It covers about 140,000 square kilometres, or a little less than 2% of the continent. For comparison, this is about the same size as North Carolina or a little larger than England.

The landscape is generally flat and sandy but there are several major features, in particular the Stirling Range near Albany, which reach 1096 metres at their highest point, and the Darling Escarpment .

The climate is temperate mediterranean. Summers are warm to hot and dry, winters are cool and wet. Mountains near the coast concentrate rainfall in that area, with parts of the extreme south-western corner receiving as much as 1,400 mm per year (about 56 inches). Away from the coast, however, precipitation drops rapidly, with inland areas averaging about 250 mm per year (10 inches).

See also:

Other Australian drainage divisions include:

• Indian Ocean drainage division: see Pilbara region of Western Australia
• Timor Sea drainage division: see Top End and Kimberley region of Western Australia
• Gulf of Carpentaria
• Australian north-east coast drainage division
• Australian south-east coast drainage division
• Murray-Darling Basin
• South Australian gulf drainage division
• Lake Eyre Basin
• Western Plateau