Lake Okeechobee, also known as Florida's Inland Sea, is the largest freshwater lake in the state of Florida. It is the eighth largest natural freshwater lake among the 50 states of the United States and the second largest natural freshwater lake contained entirely within the contiguous 48 states. Okeechobee covers 730 square miles (1,900 km ) and is exceptionally shallow for a lake of its size, with an average depth of only 9 feet (2.7 metres).