Laguna de Bay is a large shallow freshwater body in the heart of Luzon Island with an aggregate area of about and a shoreline of . It is considered to be the third largest inland body of water in Southeast Asia after Tonle Sap in Cambodia and Lake Toba in Sumatra, Indonesia. Laguna de Bay is bordered by the province of Laguna in the east, west and southwest, the province of Rizal in the north to northeast, and Metropolitan Manila in the northwest. The lake has an average depth of and its excess water is discharged through the Pasig River.