The South Esk River, the longest river in Tasmania, is a major perennial river located in the northern region of Tasmania, Australia. It is 252 km in length.
The South Esk springs from the eastern foothills of the Ben Lomond plateau near Mathinna and the rivers course describes an arc around the entire southern promontory of the mountain – running through Fingal, Avoca and Evandale before winding its way northwest through Perth, Longford and Hadspen. The river merges with the tributary Meander River, then flows through the narrows of the Cataract Gorge to finally meet the North Esk River at Launceston. From this confluence arises kanamaluka/Tamar River, which runs to the Bass Strait.
The natural river flow is interrupted by the Trevallyn Dam, near Launceston, constructed as part of the Trevallyn Power Station hydroelectric power scheme. The river is subject to flooding which overflows at Lake Trevallyn to create the spectacle of high rapids coursing through the narrows of the Gorge.
The rivers two largest tributaries are the Macquarie and Meander Rivers.
