The Trevallyn Dam is a dam on the South Esk River in Launceston, Tasmania, Australia and is used to provide water for hydroelectricity. The spillway height is 26.8 metres and the dam wall is 177 metres long. The lake has a surface area of 1.48 km² and storage capacity of 12.33 million m³. ANCOLD says that this is a Dam and lists the dam wall height as 33 metres and the completion date as 1955. The total volume of the wall is 61,000 cubic metres.
The dam diverts water to the Trevallyn Power Station through a 3.2km tunnel.