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Largest lakes & reservoirs in Illinois 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 64 articles we have published for Illinois lakes.

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Below are lakes within USA > US Midwest Region > Illinois > Compared by water volume. This list does not represent all lakes in Illinois, only the 64 Illinois lake articles we have published on the LakeLubbers website.