Copeton Dam, Embankment dam in New England region, Australia.

Copeton Dam is an embankment dam on the Gwydir River in northern New South Wales with a large reservoir for water storage. The site offers boat ramps, camping grounds, picnic facilities, and playgrounds for families.

The dam was built between 1968 and 1976 by the New South Wales Water Conservation Commission to support irrigation in the Gwydir Valley. The project was necessary to secure water supply for agricultural use in the region.

Lake Copeton, the reservoir behind the dam, is stocked with native fish such as Murray cod and golden perch, and the dam's name comes from the nearby Copeton station area. Anglers fish from the shore and by boat on the 4,620-hectare lake, and the surrounding grounds are used for camping and picnics.

The dam lies about 35 km southwest of Inverell, between Bingara and Bundarra, reached by road along the Gwydir River. Lake Copeton covers 4,620 hectares, so boat ramps and foreshore areas are spread over a wide area; plan where to launch or swim before arriving. Summer heat is strong and shade is limited, so carry water and sun protection.

The unlined spillway channel eroded through hard, unweathered granite because of rock failure under high in-situ compressive stress, a form of erosion not reported anywhere else in the world. Remedial work split the single spillway into a service spillway and a secondary emergency spillway with a training wall.