Bass Strait

Bass Strait
Map of Australia with Bass Strait marked in light blue
Location	Indian Ocean–Pacific Ocean
Coordinates	40°S 146°E / 40°S 146°E / -40; 146Coordinates: 40°S 146°E / 40°S 146°E / -40; 146
Type	Strait
Basin countries	Australia
Max. length	500 kilometres (310 mi)
Max. width	350 kilometres (220 mi)
Average depth	60 metres (200 ft)
Max. depth	155 m (509 ft)

Bass Strait /ˈbæs/ is a sea strait separating Tasmania from the Australian mainland, specifically the state of Victoria.

The International Hydrographic Organization defines the limits of Bass Strait as follows:

Some authorities consider the strait to be part of the Pacific Ocean as in the never-approved 2002 IHO Limits of Oceans and Seas draft. In the currently in-force IHO 1953 draft, it is instead listed as part of the Indian Ocean.

The Australian Hydrographic Service does not consider it to be part of the Southern Ocean, using the expanded Australian definition, and states that it lies with the Tasman Sea. The strait between the Furneaux Islands and Tasmania is Banks Strait, a subdivision of Bass Strait.

The strait was named after George Bass, after he and Matthew Flinders passed through it while circumnavigating Van Diemen's Land (now named Tasmania) in the Norfolk in 1798–99. At Flinders' recommendation, the Governor of New South Wales, John Hunter, in 1800 named the stretch of water between the mainland and Van Diemen's Land "Bass's Straits". Later it became known as Bass Strait.

The existence of the strait had been suggested in 1797 by the master of Sydney Cove when he reached Sydney after deliberately grounding his foundering ship and being stranded on Preservation Island (at the eastern end of the strait). He reported that the strong south westerly swell and the tides and currents suggested that the island was in a channel linking the Pacific and southern Indian Ocean. Governor Hunter thus wrote to Joseph Banks in August 1797 that it seemed certain a strait existed.