Fort Lac la Pluie was a fur trade depot established by the North West Company sometime between 1775 and 1787. It was located on a high bank on the west side of modern Fort Frances, Ontario across from International Falls, Minnesota on the Rainy River downstream (west) of some rapids (Chaudière portage) where the river flows out of Rainy Lake. Upstream at the outlet of the lake was the old French post of Fort Saint Pierre (1731-1758). The site is marked by a granite boulder. Morton describes some runable rapids, Fort Saint Pierre and a fall that had to be portaged before reaching the fort, which implies that the river level may have changed.