There are 7.48 gallons of water in a cubic foot, so the answer is
1,000,000 / 7.48 = 133,690 ft3
Using approximate figures, if your lake is an average of thirty feet deep and fifty feet wide, it would have to be about ninety feet long.
If you are in the UK, your lake would be 160,543 ft3 and thirty feet deep, fifty feet wide and one hundred and seven feet long.
Truman Lake in Missouri has about 11.32 million gallons of water in it. There are several types of fish in the lake as well.
Salt lak
Lake Okeechobee holds one trillion gallons of water. It is the largest lake in Florida and is the second largest body of fresh water in the contiguous United States.
Lake Chelan holds approximately 5 trillion gallons of water.
Lake Okeechobee in the state Florida U.S was formed by ocean 6000 years ago when the waters receded and by its complacity it holds approximately 1 trillion gallons of water.
There are approximately 696 billion gallons of water in Lake Winnebago.
Lake Superior holds the most water, followed by Lake Victoria, with Lake Titicaca lagging a long way behind.
Approx 756,993,907,779 gallons
Lake Pleasant, Arizona has 653062 acre-feet which is 212,801,184.619.474 gallons.
There are 6 quadrillion gallons of water in Lake St. Clair. That is one fifth of the world's fresh surface water.
There are hundreds of lakes that could have ten billion gallons of water. Lake Superior in Michigan is one of these lakes.
90 millon gallons