NIPISSING, a lake of the district of the same name in Ontario, Canada, situated nearly midway between Lake Huron and the Ottawa river, at an altitude of 64·4 ft. above the sea. It is of irregular shape, with bold shores, and contains many islands; from the north it receives the waters of Sturgeon river. It is 50 m. in length and 20 in breadth; discharges its waters by French river into Lake Huron, and is separated by a low watershed from the Mattawa river, a tributary of the Ottawa. It has been proposed as the summit level of the projected Ottawa and Georgian Bay canal, an important project rendered difficult by the numerous rapids both on French river and on the Ottawa. With the Ottawa, Mattawa and French, it formed the old voyageur route from Montreal to the Great Lakes.