Happy Jacks Dam is a major ungated concrete gravity dam across the Tumut River in the Snowy Mountains region of New South Wales, Australia. The dam's main purpose is for the generation of hydro-power and is one of the sixteen major dams that comprise the Snowy Mountains Scheme, a vast hydroelectricity and irrigation complex constructed in south-east Australia between 1949 and 1974 and now run by Snowy Hydro. The impounded reservoir is called the Happy Jacks Pondage. The dam wall is immediately downstream of the confluence of Happy Jacks Creek and the Tumut River.