What is the largest lake entirely within a single country?

The largest lake entirely within a single country is Lake Michigan in the United States.

Lake Michigan covers about 58,000 square kilometres (22,300 square miles) and is bordered by Wisconsin, Illinois, Indiana and Michigan. It is the only one of North America’s five Great Lakes located completely within one country; the other four are shared by the United States and Canada.

Lake Superior and Lake Huron are larger by surface area, which makes them tempting but incorrect choices for this wording. Lake Victoria is larger than Lake Michigan but is shared by Tanzania, Uganda and Kenya. Lake Baikal is the world’s deepest lake and contains more freshwater by volume than Lake Michigan, but it lies entirely in Russia and has a smaller surface area.

Hydrologically, Lake Michigan is connected to Lake Huron through the Straits of Mackinac. Because both lakes have the same water level, some scientific treatments consider them one connected lake, but Lake Michigan remains the standard answer to this geographic quiz question.