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The Eastmain River is a river in west central Quebec which rises in central Quebec and flows 800 km west to drain into James Bay. 'East Main' is an old name for the east side of James Bay, related to the name of an early Hudson Bay Company trading post. This river drains an area of 46,400 square kilometres (17,900 sq mi). The First Nations Cree village of Eastmain is located at the mouth of the river on the bay.

Eastmain River Dec 2005.jpg
Eastmain River in Dec. 2005 at the James Bay Road.
Eastmain map.png
Eastmain River original basin in yellow and orange. Diverted basin in orange.
Physical characteristics
SourceLac Bréhat
 ⁃ locationBaie-James, Nord-du-Québec, Québec, Canada
 ⁃ coordinates52°31′30″N 70°52′00″W / 52.52500°N 70.86667°W / 52.52500; -70.86667
 ⁃ elevation554 m (1,818 ft)
MouthJames Bay
 ⁃ location
Eastmain, Nord-du-Québec, Quebec, Canada
 ⁃ coordinates
52°14′30″N 78°34′00″W / 52.24167°N 78.56667°W / 52.24167; -78.56667Coordinates: 52°14′30″N 78°34′00″W / 52.24167°N 78.56667°W / 52.24167; -78.56667
 ⁃ elevation
0 m (0 ft)
Length756 km (470 mi)[1]
Basin size46,400 km2 (17,900 sq mi)[1]
 ⁃ average930 m3/s (33,000 cu ft/s)[1]
Basin features
 ⁃ left
 ⁃ right

Since the late 1980s, most of the waters of the Eastmain River have been diverted and flow northwards through the Opinaca Reservoir, with a surface area of about 950 km², and into the Robert-Bourassa Reservoir of Hydro-Québec's La Grande Complex. The remainder of the Eastmain River contains only about 10% of the volume of its former flow, and is now subject to freeze-up in winter (see photo). These changes have affected the Cree and Inuit peoples who live along the Eastmain River and James Bay coast.

A further hydroelectric project on the upper Eastmain River was under construction in 2005. The project was part of the original hydroelectric project provided for by the James Bay and Northern Quebec Agreement of 1975. The Eastmain Reservoir will eventually have a surface area of about 600 km² and the Eastmain-1 power plant will generate a maximum of 900 MW.

The Eastmain river was named after the Hudson's Bay Company's East Main District, which was located east and south of Hudson Bay. The mouth of the Eastmain was a center of the Hudson Bay Company fur trade. Charles Bayly reached it from Rupert House in the 1670s. After Rupert House was destroyed in 1686, the area was visited by a ship from York Factory. In 1723-24 Joseph Myatt of the Hudson's Bay Company built a post.[2]

See alsoEdit


  1. ^ a b c Atlas of Canada Archived February 2, 2007, at the Wayback Machine (all values of original river prior to hydro-electric development.)
  2. ^ Arthur S Morton, A History of the Canadian West to 1870-71, no date, circa 1950