The salty Caspian Sea has the greatest surface area of any lake at 143,200 square miles (370,886 square kilometers).
Lake Superior, on the United States/Canada border, is the named freshwater lake with the greatest surface area at 31,700 square miles (82,103 square kilometers).
However, Lake Michigan and Lake Huron can technically be considered a single lake because they both have the same surface elevation and they are connected by the Mackinac Strait (which is not a river because the water does not have a consistent flow direction). So, Lake Michigan-Huron could be considered the largest freshwater lake in the world by surface area. It has a total surface area of 45,410 square miles (117,611 square kilometers), which is significantly larger than Lake Superior. The total water volume in Lake Michigan-Huron, at 2,026 cubic miles (8,443 cubic kilometers), is much smaller than the volume of Lake Baikal.
Credit : Geology
Picture Credit : Google
