1. Lake Superior is, by surface area, the world's largest freshwater lake. 2. The surface area of Lake Superior (31,700 square miles or 82,170 square kilometers) is greater than the combined areas of Vermont, Massachusetts, Rhode Island, Connecticut, and New Hampshire. 3. Lake Superior contains as much water as all the other Great Lakes combined, even throwing in two extra Lake Eries. Its volume is second only to Russia's Lake Baikal.