Lake Izabal , also known as the Golfo Dulce, is the largest lake in Guatemala with a surface area of 589.6 km² (145,693 acres or 227.6 sq mi) and a maximum depth is 18 m (59 ft). The Polochic River is the largest river that drains into the lake. The lake which is only a metre above sea level drains into the Gulf of Honduras of the Caribbean Sea through the smaller Golfete Dulce which is at sea level and the navigable Rio Dulce.