This is the only episode featuring Toph where she doesn't use earth-bending, except to see when she is walking.
This episode marks the first time Zuko uses both Sokka and Aang's names. Although he doesn't actually say Aang's name until a later episode, he does write it on a note he left for him which Katara reads out.
Toph is shown sleeping with her feet up. Since Toph "sees" with her feet, this is the equivalent of her closing her eyes to sleep.
The Boiling Rock is inspired by Alcatraz, an infamous prison built on a small island in the San Francisco Bay near California. The bay has extremely cold water, strong currents, and is inhabited by 21 species of sharks. Alcatraz was believed to be impossible to escape because of the water around it, but three men did escape in June of 1962. It is unknown if the men survived.
Wade Williams, who provides the voice of The Warden, also played Brad Bellick, the warden in the TV show Prison Break.