Largest lakes & reservoirs in Ontario, Canada by water volume
The estimated volume of water that a lake contains is measured at the lake’s normal elevation. By this measure, the world’s largest freshwater lake is Siberia’s Lake Baikal.Water Volume can be measured in acre-feet, in cubic miles, or in cubic kilometers. One acre-foot is the amount of water needed to cover one acre (43,560 square feet) to a depth of one foot. One cubic mile equals 3,379,200 acre-feet. One cubic kilometer equals 810,713 acre-feet. 1 acre-foot is equal to 325,851 US gallons. Siberia’s Lake Baikal contains about 6,276,367,740,000,000 gallons of freshwater – nearly 1 million gallons for every living person on earth.
The other – and more widely used – measure of a lake’s size is the lake’s surface acreage. By that measure, the world’s largest freshwater lake is North America’s Lake Superior.
Note: In the United States, an acre foot is a unit of volume used to refer to large-scale bodies of water. It is defined by the volume of water needed to cover 1 acre of surface area to a depth of 1 foot.
You can find many of the the world’s largest lakes (by water volume) on LakeLubbers. Note: For some lakes, the water volume data is unknown or does not apply, so you may see fewer lakes than the total 55 articles we have published for Ontario, Canada lakes.
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Below are lakes within Canada > Ontario, Canada > Compared by water volume. This list does not represent all lakes in Ontario, Canada, only the 55 Ontario, Canada lake articles we have published on the LakeLubbers website.
Lake name  |
Water vol. in ac-ft |
Lake description |
|---|---|---|
| Lake Superior (Canada, Great Lakes of North America, Lake Superior Northwoods Region, WI, Michigan, Minnesota, Northeast Minnesota, Ontario, Canada, US Midwest Region, USA, Upper Peninsula Region, MI, Wisconsin) |
9,799,680,000 ac-ft | Skipping over state and country borders, Lake Superior, the largest, deepest, coldest, cleanest, least developed, and most pristine of the Great Lakes … |
| Lake Michigan-Huron (Canada, Chicagoland Region, IL, Great Lakes of North America, Illinois, Indiana, Lake Michigan Region, WI, Michigan, North Indiana, Northeast Michigan, Northwest Michigan, Ontario, Canada, Southwest Michigan, US Midwest Region, USA, Upper Peninsula Region, MI, West Central Michigan, Wisconsin) |
6,858,776,000 ac-ft | Lake Michigan and Lake Huron – two of North America’s Great Lakes – are contiguous and they share the same elevation of 577 feet above sea level. They … |
| Lake Huron (Canada, East Central Michigan, Great Lakes of North America, Michigan, Northeast Michigan, Ontario, Canada, US Midwest Region, USA, Upper Peninsula Region, MI) |
2,872,320,000 ac-ft | A glacial lake of epic proportions, Lake Huron is the second largest of the five Great Lakes by surface area, boasting 23,010 square miles and an incr … |
| Lake Ontario (Canada, Finger Lakes Region, NY, Great Lakes of North America, Greater Niagara Region, NY, New York, Ontario, Canada, Thousand Islands Region, NY, US Mid-Atlantic Region, USA) |
1,328,025,600 ac-ft | Lake Ontario, one of the world’s five Great Lakes, weaves over state and country borders, delighting Americans, Canadians, and visiting tourists with … |
| Lake Erie (Canada, Chautauqua-Allegheny Region, NY, Great Lakes Region, PA, Great Lakes of North America, Greater Niagara Region, NY, Michigan, New York, Northeast Ohio, Northwest Ohio, Ohio, Ontario, Canada, Pennsylvania, Southeast Michigan, US Mid-Atlantic Region, US Midwest Region, USA) |
391,987,200 ac-ft | Lake Erie, one of the Great Lakes of North America, straddles the borders of Ohio, Pennsylvania, New York, Michigan, and the Canadian province of Onta … |
| Lake of the Woods, MN / Canada (Canada, Manitoba, Canada, Minnesota, Northwest Minnesota, Ontario, Canada, US Midwest Region, USA) |
15,700,000 ac-ft | Spanning the border from Minnesota into the Canadian provinces of Ontario and Manitoba, Lake of the Woods is an enormous body of water over 68 miles l … |
| Lake Simcoe, ON (Canada, Ontario, Canada) |
9,404,273 ac-ft | Spectacular Lake Simcoe is one of the most visited vacation spots in Ontario’s south-central region. Just over an hour north of Toronto, Lake Simcoe p … |
| Lake Saint Clair, MI / Canada (Canada, Michigan, Ontario, Canada, Southeast Michigan, US Midwest Region, USA) |
2,770,944 ac-ft | (Also known as Lake St. Clair) Heart-shaped Lake Saint Clair is the smallest body of water in the Great Lakes system. Tucked between Lake Huron to the north and Lake Erie to the sou … |
| Lake St. Francis, NY / Canada (Canada, New York, Ontario, Canada, Quebec, Canada, Thousand Islands Region, NY, US Mid-Atlantic Region, USA) |
2,269,997 ac-ft | (Also known as Lac Saint-Francois) Lake St. Francis is part of the 2,340 mile system of locks, canals, and channels that link the Atlantic Ocean to the Great Lakes and the St. Lawrence … |
| Lake Muskoka, ON (Canada, Ontario, Canada) |
1,124,459 ac-ft | (Also known as Muskoka Lake, Muskoka Lakes Region) Lake Muskoka, located in Ontario’s Muskoka Lakes Region, is one of Canada’s most famous lakes. Actually a chain of lakes, Muskoka joins Lake Joseph an … |
| Mazinaw Lake (Canada, Ontario, Canada) |
555,339 ac-ft | (Also known as Upper Mazinaw Lake, Lower Mazinaw Lake) Amazing Mazinaw Lake holds court as the headwaters of Canada’s Mississippi River in eastern Ontario. This beautiful sprawling lake has alternately del … |
| Charleston Lake (Canada, Ontario, Canada) |
353,309 ac-ft | A natural haven awaits vacationers in Eastern Ontario along the shores of Charleston Lake. Balanced along the eastern edge of the Frontenac Arch geolo … |