It rises near the border between Quebec and Labrador, flows south, and enters Magpie 60 kilometres (37 mi) west of Havre-Saint-Pierre.

The central section contains the long Lake Magpie Its estuary is wide and forms a harbour for fishing boats.

The village boomed after the fishing companies Robin & Colas and Le Bouthillier establish facilities there around 1870.

The river is named for the Canada jay (Perisoreus canadensis), which the English called "magpie".

This watercourse is quite difficult to navigate, since it is broken by a series of falls and rapids from its mouth to a distance of about thirty four miles upstream.

[5] A map of the ecological regions of Quebec shows the river in sub-regions 6j-T and 6m-T of the east spruce/moss subdomain.

[6] In 2004, a plan by a private company to construct a small hydroelectric plant on the river generated protests by environmentalists.

The Bureau of Public Hearings on the Environment (BAPE) gave a favorable report on the project in 2004, but said there should be no further development on the river.

[7]In August 2005 the Charest government authorized construction of the dam by decree, which would eliminate some famous rapids.

In view of the rapidly declining Atlantic salmon population catch-and-release should have been implemented on all rivers apart from northern Quebec.

[13] The lower section of the West Magpie provides 50 kilometres (31 mi) of challenging conditions for class IV – V whitewater kayak and open boat paddlers.