The lake serves as a major water supply reservoir for a large portion of the greater metropolitan Sydney area.
Before the construction of the dam, Burragorang Valley, as well as the nearby Megalong Valley had been inhabited by the Dharug and Gundungurra Aboriginal people for thousands of years.
In the 19th century, white settlers arrived in the area. A number of farming towns and coal mines were located in the area. All of these are now underwater.