What is the name of the frozen lake at the bottom of Hell?

Cocytus is the frozen lake at the bottom of Hell in Dante’s Inferno. Dante places it in Hell’s deepest region, where traitors are imprisoned beneath the ice rather than tormented by ordinary flames.

The lake is divided into four zones named for famous betrayers: Caina for traitors to relatives, Antenora for traitors to their political communities, Ptolomea for traitors to guests, and Judecca for traitors to their benefactors. The classification makes betrayal the gravest sin in Dante’s moral structure.

At the center of Judecca stands Lucifer, frozen in the ice up to his waist or chest depending on the translation and depiction. His enormous wings beat constantly, creating the freezing wind that keeps Cocytus solid. Dante and Virgil climb down Lucifer’s body and pass through the center of the Earth before beginning their ascent toward Purgatory.

Readers often confuse Cocytus with the rivers Styx, Acheron, and Phlegethon. Those are separate bodies of infernal water; only Cocytus is the final frozen lake.