The lake is located to the south of the castle at the bottom of the cliff. It is approximately a half-mile in diameter.

Various creatures inhabit the lake, including a giant squid, merfolk, and grindylows.

Some students often come out here for a swim to cool off when the water is nice, usually in the late summer when school has just begun or in the spring, when school is just getting out.

There's a rumor going around that they are going to freeze the lake over to have a ice-ball outside during the Winter, but it's just a rumor.