river, north central Ontario, Canada, rising in Lake St. Joseph at an elevation of 1,218 ft (371 m) and flowing generally eastward into James Bay. For 250 mi (400 km) of its 610-mi course, the river is navigable, and it served as an important route during the fur-trading days, when boats sailed inland from the Hudson's Bay Company post of Ft. Albany (established 1684) at the mouth. Its largest tributary is the Kenogami River, which is 200 mi long. The flow of the Ogoki River, a former tributary, has been diverted into Lake Nipigon (Nipigon, Lake) to increase the hydroelectric output at the Nipigon River power sites.