Ontario is the second largest Canadian province by land area and the largest by population. At one time in the past, all of Ontario was covered by glaciers. However, about 10,000 years ago, the last ice sheet that covered the province receded and as a result, many lakes were formed together with the beginnings of the Great Lakes. Ontario has many lakes in a variety of sizes. Sixteen lakes in Ontario have an area greater than 150 square miles, of which Lake Superior is the biggest of all.
5. Lake Nipigon
Lying 850 feet above sea level, Lake Nipigon is the largest lake that is wholly found in the province of Ontario in Canada. Nipigon is also a part of the Great Lake drainage Basin. With a total area of 1,872 square miles, Lake Nipigon drains into the Nipigon River, and together they form the largest tributaries of Lake Superior. The largest islands on the lake include Katatota Island, Logan Island, Shakespeare Island, Murchison Island, Caribou Island, Kelvin Island, Murray Island, and Greek Island. The lake has a maximum depth of 541 feet.
4. Lake Ontario
Lake Ontario is the fifth largest of North America's five Great Lakes and the fourth largest in Ontario by surface area with approximately 7,340 square miles, lying at an elevation of 246 feet above sea level with 802 feet maximum depth. The primary inlet for Lake Ontario is the Niagara River. The lake drains into the Atlantic Ocean through the St. Lawrence River. It is the world's 14th largest lake.
3. Lake Erie
Lake Erie is the fourth largest of North America's five Great Lakes by surface area, the third largest in Ontario, and the 13th largest lake in the world. The lake has a total area of 9,900 square mile and a 210-foot maximum depth. It lies at an elevation of 571 feet above sea level. The lake is bounded by the US states of Michigan to the west, Pennsylvania to the eastern shore and New York to the southern shore. The lake was named Erie due to its unpredictable and sometimes dangerous and violent nature ("Erie" comes from the Iroquoian word "Erige", meaning "cat").
2. Lake Huron
Lake Huron is Ontario's second largest lake and the third largest of North America's five Great Lakes with an area of 23,000 square miles. The lake is bordered by the province of Ontario in Canada and the US state of Michigan. St. Marys River is the primary inlet of Lake Huron while the main outlet is the St. Clair River. The lake has a 750-foot maximum depth and a surface elevation of 581 feet.
1. Lake Superior
With an area of 31,700 square miles, Lake Superior is not only the largest lake in Canada's Ontario province but also the largest of North America's five Great Lakes. The lake is bordered on the north by Ontario, to the west by the state of Minnesota in the US and to the south by the American states of Wisconsin and Michigan. Lake Superior is considered as the largest freshwater lake in the world regarding the surface area. By volume, Lake Superior is the third largest freshwater lake in the world and the largest in North America. The lake has a surface elevation of 604feet and a maximum depth of 1,333 feet.