The dam, located 19 kilometres (12 mi) west of Hudson's Hope, and 85 kilometres (53 mi) northwest of Chetwynd, is named after the late former premier William A. C. Bennett, and came on-line in 1968. During the planning and construction phase it was called the "Portage Mountain Development."
The complex consists of the main earth-fill dam, which holds back Williston Lake, and the underground Gordon M. Shrum Generating Station. It is capable of generating 2,730 megawatts of electricity at peak capacity. The dam is constructed 660 m (2,170 ft) above sea level.