Great Lakes Quickfacts

Have you ever wondered what makes the Great Lakes great? Here are some facts about the Great Lakes that highlight their unique history, physical features, population and resource contributions.

The facts in this list originate from various third-party sources considered to be authoritative. For information on the source material, contact

History and Physical Features

  1. Many of the lakes on the Canadian Shield, including the Great Lakes, were created by glacial erosion.
  2. The combined shoreline of the Great Lakes is equal to about 45% of the earth's circumference.
  3. The Great Lakes Basin covers an area greater than 750 000 square kilometres.
  4. The river in Canada with the greatest annual discharge is the St. Lawrence River at 9 850 cubic metres per second.
  5. Canada's longest inland waterway stretches 3 700 kilometres from the Gulf of St. Lawrence to Lake Superior.
  6. The Great Lakes are the largest system of fresh surface water on earth, containing roughly 18% of the world's fresh surface water.
  7. Only 1% of the waters of the Great Lakes are renewed each year by snow melt and rain.
  8. The most severe flood in Canadian history occurred on October 14 to 15, 1954 when Hurricane Hazel brought 214 millimetres of rain in Toronto region in just 72 hours.
  9. Floods are the most costly natural disasters in Canada in terms of property damage.
  10. Passage of a major storm on Lake Erie can cause short-term lake level changes of as much as 4 metres.
  11. The first Canadian Heritage River was the French River in Ontario, designated in 1986.

Population and Resource Contributions

  1. Almost 60% of the world's fresh water falls within a transboundary basin like the Great Lakes; where at least one of the tributaries crosses a political boundary.
  2. Forty percent of Canada's boundary with the United States is composed of water.
  3. The Great Lakes Basin is home to 90% of Ontario's population and 40% of Canada's economic activity.
  4. The Great Lakes support 33 million people, including nine million Canadians and eight of Canada's 20 largest cities.
  5. The Great Lakes provide drinking water to 8.5 million Canadians.
  6. The Great Lakes support 25% of Canada's agricultural capacity.
  7. Each year, the Great Lakes contribute $180 billion to Canada-U.S. trade.
  8. Every year, 1.5 million recreational boaters enjoy the Great Lakes.
  9. The Great Lakes support 45% of Canada's industrial capacity.
  10. The Great Lakes sustain a $100 million commercial fishing industry.
  11. The Great Lakes sustain a $350 million recreational fishing industry.
  12. The wetlands of Lake Ontario have suffered severe loss over the last two centuries due to agricultural drainage and urban encroachment.

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