The Nullarbor Plain 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 piece of limestone, 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 between South Australia (SA) and Western Australia (WA).