Churchill River, 1609 km long, issues from Churchill Lake in northwestern Saskatchewan and flows southeast, east and northeast across the lowlands of northern Saskatchewan and Manitoba to Hudson Bay at CHURCHILL, Man. Along its course are rapids, falls, narrow chutes, long placid stretches of smooth water, and - typical of rivers of the Canadian SHIELD - a chain of interconnected lakes. Many of the lakes are elongated in the dominant direction of the flow of the last continental ice sheet. The largest of these lakes are SOUTHERN INDIAN LAKE (2015 km2), Peter Pond Lake (777 km2), Churchill Lake (543 km2), Granville Lake (429 km2) and Lac Île-à-la-Crosse (391 km2), where the river takes in its main tributary, the Beaver River (491 km). The name - for John Churchill, first duke of Marlborough, governor of the Hudson's Bay Company from 1685 to 91 - was applied to the river as early as 1686; the Cree called it Missinipi, meaning "big river."
The river was travelled by Cree and Chipewyan, and Jens MUNK
wintered at its mouth in 1619-20. The Hudson's Bay Company built a post near its mouth in 1717; it was called Churchill River, Churchill, and Churchill Factory until 1719, when the name was changed to PRINCE OF WALES FORT
. In 1782 the post was destroyed; Samuel HEARNE
re-established it some 8 km upriver. The North West Company began using the Churchill River after Joseph FROBISHER
established a trade link between it and the Montréal route via the Saskatchewan and Sturgeon Weir rivers and Frog Portage. He built a fur-trade post on Lac Île-à-la-Crosse in 1776, and soon many small competing posts were built along the river.
A hydroelectric station at Island Falls, Sask, was built in 1929 to supply power to the mining region of FLIN FLON
, Man. And, at the north end of Southern Indian Lake, an artificial diversion channel routes 60% of the river's flow to the NELSON RIVER
for hydroelectric power generation. This last project was completed in 1976 after much political wrangling. One result of the much-reduced flow of the Churchill has been the large-scale environmental impact on fur-bearing animals, shorebirds, waterfowl and fish populations. In the late 1990s, the construction of a weir some 13 km from the river's mouth raised the water level of a section of the river below Southern Indian Lake.