The Port River is the western branch of the largest tidal estuary on the eastern side of Gulf St Vincent. It extends inland through the historic Inner Harbour of Port Adelaide, to the constructed salt-water West Lakes in the north-western suburbs of Adelaide, the capital of South Australia. The lower reaches of the Port River flow between the Lefevre Peninsula, and the Section Bank and Torrens Island, and form the sea entrance to the port facilities of Adelaide, and connect to the Barker Inlet to the east via the North Arm and Angas Inlet which surround Garden Island. Before European settlement of Adelaide's western suburbs and the construction of various flood mitigation channels and levees, the Port River formed one of the outlets of the River Torrens.