Lake St Clair or leeawulenna is a natural freshwater lake located in the Central Highlands area of Tasmania, Australia. The lake forms the southern end of the Cradle Mountain-Lake St Clair National Park. It has an area of approximately 45 square kilometres (17 sq mi), and a maximum depth of 215 metres (705 ft), making it Australia's deepest lake.

The River Derwent, also known as timtumili minanya in palawa kani, is a significant river and tidal estuary in Tasmania, Australia. It begins its journey as a freshwater river in the Central Highlands at Lake St Clair, descending over 700 metres (2,300 ft) across a distance of more than 200 kilometres (120 mi). At the settlement of New Norfolk in the Derwent Valley its waters become brackish, flowing through Hobart, the capital city of Tasmania, its seawater estuary eventually empties into Storm Bay and the Tasman Sea.