Lake, southeastern Ontario, Canada.
Located midway between the Ottawa River and Georgian Bay , it is 50 mi (80 km) long and 30 mi (48 km) wide, with an area of 321 sq mi (832 sq km). A remnant of glacial Lake Algonquin, it contains many islands. The French River drains the lake as it flows west into Georgian Bay. It was discovered by Étienne Brûlé с 1610 and was later a fur-trading route linking the Ottawa River with the upper Great Lakes .