Canadian Geographic
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The Great Lakes

With at least two million lakes within her borders, Canada likely has more lakes than any other country in the world. Five-hundred and sixty three of Canada’s lakes are larger than 100 square kilometres. Quebec alone is home to more than 8,200 lakes.

Canada’s largest set of lakes, the Great Lakes, are shared with the U.S. and form the international boundary. At 22,810 cubic kilometres combined, the lakes comprise approximately 22 per cent of the world’s freshwater. The Great Lakes region is comprised of not only the lakes, but also numerous smaller lakes, rivers and some 35,000 islands. Approximately 8.5 million Canadians and 30.7 million Americans live in the Great Lakes basin, in cities including Toronto, Kingston, Sarnia, Hamilton and Thunder Bay.

The largest of the Great Lakes is Lake Superior, which covers 83,300 square kilometres, making it the second largest freshwater lake in the world, after the Caspian Sea. Covering 59,800 square kilometres, Lake Huron is the second largest of the Great Lakes, and the world’s fourth largest lake. Following closely behind is the world’s fifth largest lake, Lake Michigan, which is the only one of the Great Lakes to be located entirely within the U.S. boundary; all the other Great Lakes are shared by both countries. Lake Erie is the world’s tenth largest lake, and Lake Ontario is the world’s thirteenth largest.

The management of many aspects of the Great Lakes is overseen by the International Joint Commission, which is based in Detroit, Michigan. The Great Lakes Waterway provides a major North American transportation corridor. The lakes are also valuable sources of hydroelectricity, and are bustling centres for industry, agriculture and commerce. The unique climate of the region, created by the “lake effect”, which moderates seasonal temperatures, allows for orchards and vineyards to thrive further north than in other parts of North America.

The Great Lakes are estimated to have formed about 10,000 years ago, at the end of the last ice age. When the Laurentide ice sheet retreated, it left behind a large amount of meltwater, which in turn filled the basins that had been carved out by the glaciers.


This interactive piece features a cross-section diagram of the Great Lakes, and their varying depth and elevation. Users can also select to learn about the Great Lakes Basin, supported by a map and narrated description.


On the next page:

Transportation corridors

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Quiz :

In what year was the International Joint Commission established?