Nicaragua, Lake, 3,089 sq mi (8,001 sq km), c.100 mi (160 km) long and up to 45 mi (72 km) wide, SW Nicaragua; the largest lake of Central America. It is drained into the Caribbean Sea by the San Juan River. Lake Nicaragua, along with Lake Managua (which drains into it from the northwest), occupies part of the Nicaragua Depression, an extensive lowland region stretching across the isthmus. Once part of the sea, the lake was formed when the land rose. There are several islands in the lake (the largest is Isla de Ometepe); and small volcanoes rise above its surface. The freshwater of Lake Nicaragua contains fish usually associated with saltwater, including tuna and sharks, which have adapted to the environmental change. The lake is a transportation route; Granada is its chief port. Located only 110 ft (34 m) above sea level, the lake reaches a depth of 84 ft (26 m). It was to be an important link in the proposed Nicaragua Canal.