Lake Piso is a saltwater lake in Liberia, West African country. It is the largest lake in the country. Lake Piso has an open connection to the Atlantic Ocean, making it a tidal lagoon. The lake basin is known for the richness of its biodiversity, its diverse ecosystems and its natural beauty. The people living in the vicinity of the lake depend on the lake for fishing, and also on the high-quality diamonds that are being mined from the rivers flow into Lake Piso.