Answer:
Lake Michigan and Lake Huron
Explanation:
Lake Michigan and Lake Huron - two of North America's Great Lakes - are contiguous and they share the same elevation of 577 feet above sea level. They are connected by the five-mile-wide Straits of Mackinac. Hydrologically, this makes these "two lakes" a single lake.
Some hydrologists designate the combined entity of Lake Michigan and Lake Huron as "Lake Michigan-Huron."