 Flinders identified its boundaries with the following adjoining bodies of water - Gulf St Vincent and Backstairs Passage.The Strait’s boundary with Gulf St Vincent is the line from Troubridge Point on Yorke Peninsula to Cape Jervis on Fleurieu Peninsula.Its boundary with Backstairs Passage is the line from Cape Jervis on Fleurieu Peninsula to Kangaroo Head (west of Penneshaw) on Kangaroo Island.