Lake Alexandrina is a coastal freshwater lake located between the Fleurieu and Kangaroo Island and Murray and Mallee regions of South Australia, about 100 kilometres south-east of Adelaide. The lake adjoins the smaller Lake Albert (together known as the Lower Lakes) and a coastal lagoon called The Coorong to its southeast, before draining into the Great Australian Bight via a short, narrow opening known as Murray Mouth.
Lake Alexandrina is located north of Encounter Bay and east of Fleurieu Peninsula.
The lake empties into the Southern Ocean via a channel known as the Murray Mouth, south-east of the town of Goolwa, but when the river flow is low, the mouth is often blocked by a sand-bar.
Its Surface area is 64,900 ha.
