Hindmarsh Island is an inland river island located in the lower Murray River near the town of Goolwa, South Australia.

The Murray River is a river in Southeastern Australia. It is Australia's longest river at 2,508 km (1,558 mi) extent. Its tributaries include five of the next six longest rivers of Australia. Together with that of the Murray, the catchments of these rivers form the Murray–Darling basin, which covers about one-seventh the area of Australia. It is widely considered Australia's most important irrigated region.