The James Bay territory, located in Northern Québec, Canada, lies between the 48th and 55^th North parallels and covers 350,000 km² (135,187 sq. mi.).

The La Grande complex was constructed to produce electric power from the Grande Rivière and from the Caniapiscau and Eastmain rivers, which both have significant proportions of their flow diverted into the Grande Rivière catchment.

In its entirety, the complex is one of the largest hydropower installations in the world, with a generating capacity of 15,238 MW. The two-phase project comprised eight generating stations and required the impounding of eight reservoirs with a total surface area of 12,953 km², including 10 809 km² of flooded terrestrial area.

The complex is serviced by the longest high voltage transmission system in North America and cost upwards of 20 billion US dollars to build.