The Nullarbor Plain (/ˈnʌlərbɔːr/ NUL-ər-bor; Latin: nullus, "no", and arbor, "tree") is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to its north. It is the world's largest single exposure of limestone bedrock, and occupies an area of about 200,000 square kilometres (77,000 sq mi). At its widest point, it stretches about 1,100 kilometres (684 mi) from east to west across the border between South Australia and Western Australia.
Historically, the Nullarbor, considered by Europeans to be almost uninhabitable, was used by the semi-nomadic Aborigines, the Spinifex and Wangai peoples.
The first Europeans known to have sighted and mapped it were an expedition led by Pieter Nuyts in 1626–27. While the interior remained little known to Europeans over the next two centuries, the name Nuytsland was often applied to the area adjoining the Great Australian Bight. It survives as two geographical names in West Australia : Nuytsland Nature Reserve and Nuyts Land District.