
The Backstairs Passage is a strait in South Australia lying between Fleurieu Peninsula on the Australian mainland and Dudley Peninsula on the eastern end of Kangaroo Island. The western edge of the passage is a line from Cape Jervis on Fleurieu Peninsula to Kangaroo Head on Kangaroo Island. The Pages, a group of islets, lie in the eastern entrance to the strait. About 14 km wide at its narrowest, it was formed by the rising sea around 13,000 years ago, at the end of the Pleistocene era, when it submerged the land connecting what is now Kangaroo Island with the Fleurieu Peninsula. Backstairs Passage was named by Matthew Flinders whilst he and his crew on HMS Investigator were exploring and mapping the coastline of South Australia in 1802.

Antechamber Bay is a locality in the Australian state of South Australia located on the north coast of Dudley Peninsula on Kangaroo Island overlooking Backstairs Passage about 108 kilometres south of the state capital of Adelaide and about 15 kilometres east of Penneshaw.

Cuttlefish Bay is a locality in the Australian state of South Australia located on the north coast of Dudley Peninsula on Kangaroo Island overlooking Backstairs Passage about 106 kilometres south of the state capital of Adelaide and about 8 kilometres east of Penneshaw. Its boundaries were created in March 2002 while its name was derived from Cuttlefish Bay, a bay located on its coastline with Backstairs Passage. Land use within the locality is concerned with agriculture while land adjoining the coastline has additional statutory constraints to “conserve the natural features of the coast.” Cuttlefish Bay is located within the federal division of Mayo, the state electoral district of Mawson and the local government area of the Kangaroo Island Council.

Cape Jervis is a town in the Australian state of South Australia located near the western tip of Fleurieu Peninsula on the southern end of the Main South Road approximately 88 kilometres (55 mi) south of the state capital of Adelaide.

Cape Jervis is a headland located at the most westerly part of the Fleurieu Peninsula on the east coast of Gulf St Vincent in South Australia about 0.7 kilometres west of the town of the same name, Cape Jervis. It is the eastern end of the opening to Gulf St Vincent.

Cape Jervis Lighthouse is a lighthouse located at the headland of Cape Jervis on the most westerly part of the Fleurieu Peninsula on the east coast of Gulf St Vincent in South Australia.

Kangaroo Head is a headland in the Australian state of South Australia located at the north-west tip of Dudley Peninsula on Kangaroo Island. It was named by the British explorer, Matthew Flinders, on 23 March 1802.
Kangaroo Island SeaLink is a South Australian ferry company and tour operator owned by SeaLink Travel Group, which has plied the crossing from mainland South Australia to Kangaroo Island since 1989. From 1989 to 1994, Kangaroo Island Sealink was owned by the Malaysian company MBF. In 1994 the company was sold to a consortium of staff members and Kangaroo Island residents. SeaLink's two currently operating ferries, Sealion 2000 and Spirit of Kangaroo Island, cross Backstairs Passage from Cape Jervis to Penneshaw in about 45 minutes, up to 10 times daily.

Moncrieff Bay is a bay in the Australian state of South Australia located at the east end of the Dudley Peninsula on Kangaroo Island in the gazetted locality of Willoughby overlooking Backstairs Passage about 106 kilometres (66 mi) south-west of the state capital of Adelaide and about 47 kilometres (29 mi) south-east of the municipal seat of Kingscote.

The Pages is an island group in the Australian state of South Australia consisting of two small islands and a reef located in Backstairs Passage, a strait separating Kangaroo Island and the Fleurieu Peninsula. The island group has been located with the protected area known as The Pages Conservation Park since 1972.

The Pages Conservation Park is a protected area in the Australian state of South Australia which is associated with the island group known as The Pages located in Backstairs Passage about 25 kilometres south-east of Cape Jervis and about 98 kilometres south south-west of the state capital of Adelaide.
For Pennshaw in the UK, see Penshaw

Pink Bay is a bay in the Australian state of South Australia and is located at the east end of Dudley Peninsula on Kangaroo Island overlooking Backstairs Passage in the gazetted locality of Willoughby about 110 kilometres (68 mi) south of the state capital of Adelaide and about 20 kilometres (12 mi) east of Penneshaw.

Cape St Albans is a headland in the Australian state of South Australia located on the north coast of the Dudley Peninsula on Kangaroo Island in the gazetted locality of Willoughby about 18 kilometres south-east of the town of Penneshaw.
Sealion 2000 is a vehicular ferry operated by Kangaroo Island SeaLink on the 18 kilometre Cape Jervis to Penneshaw route across Backstairs Passage along with the Spirit of Kangaroo Island. These two ferries provide the main form of transport to Kangaroo Island operating up to 10 trips daily. This vessel is specifically made for passengers and cars and is a larger boat. Unlike the Spirit of Kangaroo Island which is a freight boat, used for transporting trucks as well as passengers.

Cape Willoughby is a headland in the Australian state of South Australia located on the east end of the Dudley Peninsula on Kangaroo Island in the gazetted locality of Willoughby about 22 kilometres south east of the town of Penneshaw.