Kangaroo Island (Kaurna: Karta Pintingga, lit. 'Island of the Dead') is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, 112 km (70 mi) southwest of Adelaide. Its closest point to the mainland is Snapper Point in Backstairs Passage, which is 13.5 km (8.4 mi) from the Fleurieu Peninsula.

The native population that once occupied the island (sometimes referred to as the Kartan people) disappeared from the archaeological record sometime after the land became an island following the rising sea levels associated with the Last Glacial Period around 10,000 years ago. It was subsequently settled intermittently by sealers and whalers in the early 19th century, and from 1836 on a permanent basis during the British colonisation of South Australia.

Since then the island's economy has been principally agricultural, with a southern rock lobster fishery and with tourism growing in importance. The largest town, and the administrative centre, is Kingscote. The island has several nature reserves to protect the remnants of its natural vegetation and native animals, with the largest and best-known being Flinders Chase National Park at the western end.

The island is 145 kilometres (90 mi) long west/east and between 0.94 and 54 km (1 and 34 mi) from its narrowest to widest north/south points. Its area covers 4,405 km² (1,701 sq mi). Its coastline is 540 km (336 mi) long, and its highest point of 307 metres (1007 ft) is in Flinders Chase National Park, west of the junction of the Playford and West End Highways. The second highest point is Mount MacDonnell at 299 m (981 ft) above sea level. It is separated from Yorke Peninsula to the northwest by Investigator Strait and from Fleurieu Peninsula to the northeast by Backstairs Passage. A group of islets, the Pages, lie off the eastern end of the island.

Kangaroo Island separated from mainland Australia around 10,000 years ago, due to rising sea level after the last glacial period. Known as (Karta) Pintingga ('Island of the Dead') by the mainland Aboriginal peoples, the existence of stone tools and shell middens shows that Aboriginal people once lived on Kangaroo Island. It is thought that they occupied it as long ago as 16,000 years before the present and may have only disappeared from the island as recently as 2000 years ago. There is however evidence of the Kartan people on the mainland, for instance at Hallett Cove.

A mainland Aboriginal dreaming story tells of the Backstairs Passage flooding:

Long ago, Ngurunderi's two wives ran away from him, and he was forced to follow them. He pursued them and as he did so he crossed Lake Albert and went along the beach to Cape Jervis. When he arrived there he saw his wives wading half-way across the shallow channel which divided Naroongowie from the mainland. He was determined to punish his wives, and angrily ordered the water to rise up and drown them. With a terrific rush the waters roared and the women were carried back towards the mainland. Although they tried frantically to swim against the tidal wave they were powerless to do so and were drowned.

On 23 March 1802, British explorer Matthew Flinders, commanding HMS Investigator, named the land "Kanguroo (sic) Island", due to the endemic subspecies of the western grey kangaroo, Macropus fuliginosus fuliginosus, after landing near Kangaroo Head on the north coast of the Dudley Peninsula. He was closely followed by the French explorer Commander Nicolas Baudin, who was the first European to circumnavigate the Island and who mapped much of the island (which is why so many areas have French names).^{[citation needed]}