Old Adaminaby and Lake Eucumbene are the heritage-listed former town of Adaminaby and the reservoir that flooded the town, now at Eucumbene, Snowy Valleys Council, New South Wales, Australia. The town was established in 1830. The reservoir was designed by the Snowy Hydro Electric Authority and built from 1956 to 1958 by the Authority. It is also known as Old Adaminaby and Lake Eucumbene, including relics and movable objects, Eucumbene River, Eucumbene Valley, Old Adaminaby Remains, Old Adaminaby Ruins and Old Adaminaby Drowned Landscape. The property is owned by Snowy Hydro Limited, a statutory corporation owned by the governments of Australia, New South Wales and Victoria. The site was added to the New South Wales State Heritage Register on 3 June 2008.