Alligator Lake is located in Barangay Tadlac, in the hot springs resort town of Los Baños ('The Baths' in English) near the border with Calamba City in the province of Laguna. The lake is contained in a piece of land jutting out to the Laguna de Bay that was known as Malilimbas Point, and is directly situated below the northeastern slope of Mount Makiling, the highest mountain in the Laguna Volcanic Field. Because of its origin, the lake has no outlet and is replenished only by rainfall.