What is the name of the Fire Nation prison from which Sokka and Zuko escape?

The Fire Nation prison from which Sokka and Zuko escape is the Boiling Rock.

The Boiling Rock is the Fire Nation’s highest-security prison, built on an island surrounded by a lake of scalding water. In Book Three: Fire, Sokka travels there with Zuko to rescue prisoners captured during the failed invasion, including Sokka’s father, Hakoda, and later Suki.

Sokka and Zuko initially infiltrate the prison by disguising themselves as guards. Their escape plan becomes more complicated when their identities are exposed and they must work with Suki and the prisoner Chit Sang. They eventually use an ice-based isolation chamber as a makeshift boat to cross the boiling lake.

The prison is sometimes confused with other Fire Nation facilities seen in the series, but “The Boiling Rock” is both the location’s official name and the title of the two-part story. The episodes are chapters 14 and 15 of Book Three: Fire.