Investigator Strait is a body of water in

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

lying between the

Yorke Peninsula The Yorke Peninsula is a peninsula located northwest and west of Adelaide in South Australia, between Spencer Gulf on the west and Gulf St Vincent on the east. The peninsula is separated from Kangaroo Island to the south by Investigator Strai ...

, on the

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

n mainland, and

Kangaroo Island Kangaroo Island, also known as Karta Pintingga (literally 'Island of the Dead' in the language of the Kaurna people), is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, southwest ...

. It was named by

Matthew Flinders Captain Matthew Flinders (16 March 1774 – 19 July 1814) was a British navigator and cartographer who led the first inshore circumnavigation of mainland Australia, then called New Holland. He is also credited as being the first person to u ...

after his ship, HMS ''Investigator'', on his voyage of 1801–1802. It is bordered by the

Gulf St Vincent Gulf St Vincent, sometimes referred to as St Vincent Gulf, St Vincent's Gulf or Gulf of St Vincent, is the eastern of two large inlets of water on the southern coast of Australia, in the state of South Australia, the other being the larger Sp ...

in the northeast.

Discovery and exploration

It was named Investigator’s Strait by Flinders on Monday 29 March 1802.

Extent

Investigator Strait is bounded by Yorke Peninsula to its north and by Kangaroo Island to its south. Flinders identified its boundaries with the following adjoining bodies of water -

and

Backstairs Passage 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 ...

. The Strait’s boundary with

is the line from

Troubridge Point Troubridge Point is a headland in the Australian state of South Australia located on the south coast of Yorke Peninsula about south west of Edithburgh. It is the western end of the opening to Gulf St Vincent. Description Troubridge Point is ...

on Yorke Peninsula to

Cape Jervis 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 south of the state capital of Adelaide. It is named after the headla ...

on Fleurieu Peninsula. Its boundary with

is the line from

Fleurieu Peninsula The Fleurieu Peninsula () is a peninsula in the Australian state of South Australia located south of the state capital of Adelaide. History Before British colonisation of South Australia, the western side of the peninsula was occupied by the K ...

Kangaroo Head 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. Description Kangaroo Head i ...

(west of

Penneshaw Penneshaw is a township in the Australian state of South Australia located on the northeast coast of the Dudley Peninsula on Kangaroo Island about south of the state capital of Adelaide. It is the island's main ferry port with regular services ...

) on Kangaroo Island. Flinders noted that Backstairs Passage is a body of water separate to Investigator Strait. The boundary between the strait and

Nepean Bay Nepean Bay is a bay located on the north-east coast of Kangaroo Island in the Australian state of South Australia about south-south-west of Adelaide. It was named by the British navigator, Matthew Flinders, after Sir Evan Nepean on 21 March 1 ...

on the north-east coast of Kangaroo Island is a line between

Point Marsden Point Marsden (also called Marsden Point) is a headland located on the north coast of Kangaroo Island in South Australia. It was named after William Marsden, Second Secretary to the Admiralty by Matthew Flinders in 1802. It is the western ...

and Kangaroo Head. The Strait’s western boundary by definition is the line from Cape Spencer on Yorke Peninsula to Cape Borda on Kangaroo Island.

Protected areas

A number of

protected areas Protected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the ena ...

are located both within and adjoining the Strait’s extent.

Aquatic reserves

Troubridge Hill Troubridge Hill is a hill on the south coast of Yorke Peninsula in South Australia located in the locality of Honiton about south west of Edithburgh and about west of Troubridge Point. It was discovered, reported as being a ’hummock upon th ...

west of

on the south coast of Yorke Peninsula.

Marine parks

Southern Spencer Gulf Marine Park Southern may refer to: Businesses * China Southern Airlines, airline based in Guangzhou, China * Southern Airways, defunct US airline * Southern Air, air cargo transportation company based in Norwalk, Connecticut, US * Southern Airways Express, M ...

- the west end of the strait including the coasts of both Yorke Peninsula and Kangaroo Island. *

Lower Yorke Peninsula Marine Park Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...

- east end of the strait adjoining the south coast of Yorke Peninsula. *

Western Kangaroo Island Marine Park __NOTOC__ Western Kangaroo Island Marine Park (formerly Western Kangaroo Island Commonwealth Marine Reserve) is a marine protected area located south of South Australia in waters within the Australian Exclusive economic zone to the south-west ...

- west end of the strait adjoining the north coast of Kangaroo Island. *

Encounter Marine Park Encounter Marine Park is a marine park in South Australia. It is in the Fleurieu Peninsula in state of South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part ...

covers the east end of the strait including its boundaries with Nepean Bay and Backstairs Passage.

National parks and other reserves

The following reserves are located on the south coast of Yorke Peninsula (from west to east): * Innes National Park (includes Chinamans Hat Island) * Point Davenport Conservation Park The following reserves are located on the north coast of Kangaroo Island (from west to east): *

Flinders Chase National Park Flinders Chase National Park (formerly Flinders Chase) is a protected area in the Australian state of South Australia located at the west end of Kangaroo Island about west-south west of the state capital of Adelaide and west of the municipal ...

* Cape Torrens Wilderness Protection Area *

Western River Wilderness Protection Area Western River Wilderness Protection Area, formerly the Western River Conservation Park and the Western River National Park, is a protected area in the Australian state of South Australia located on the north coast of Kangaroo Island about wes ...

The following reserve is located on Althorpe Islands, Haystack Island and Seal Island at the north-west end of the strait: *

Althorpe Islands Conservation Park Althorpe Islands Conservation Park is a protected area in the Australian state of South Australia occupying the Althorpe Island, Haystack Island and Seal Island (Investigator Strait), Seal Island in Investigator Strait near the town of Stenhouse ...