triangular inlet of the Indian Ocean, on the southeast coast of South Australia, between Yorke Peninsula to the west and the mainland. About 90 mi (145 km) long and 45 miles (73 km) wide, it is linked with the ocean by Investigator Strait to the southwest, passing north of Kangaroo Island and by Backstairs Passage to the southeast. The Gawler, Torrens, and Onkaparinga rivers empty into the gulf near Adelaide. The shores are mostly low and sandy, and high salinity and hot solar evaporation have favoured an important salt industry based at Dry Creek near Port Adelaide, on the east coast. The gulf was investigated in 1802 by the English explorer Matthew Flinders and was named after Admiral John Jervis, Earl of St. Vincent. Port Adelaide, South Australia's leading port, is on the eastern side of the gulf.