Lake Torrens stretches approximately 250 kilometres (155 mi) in length and 30 kilometres (19 mi) in average width. It is Australia’s second largest lake when filled with water and encompasses an area of 5,745 square kilometres (2,218 sq mi).
The Lake Torrens catchment is an endorheic basin, having no outflow of water to the ocean.
Approximately 35,000 years ago, the lake water was fresh to brackish, but has become increasingly saline since. The traditional owners of the area are the Arabunna peoples to the north, the Kokatha to the west and the Kyuni to the east. The first European to see the lake was Edward Eyre in 1839 who spotted the salt bed from Mount Arden at the head of the Spencer Gulf. Eyre named the lake after Colonel Robert Torrens who was one of the founders of the South Australian colony.
The lake filled in 1897 and again in April 1989. It has a thin salt crust with red-brown clays beneath, which are soft and boggy. The area around the lake is sparsely vegetated with samphire, saltbush and bluebush.