Dereks room is Prince Derek's personal bedroom within Dreamland Castle
The room contains a bed, at least two cabinets, and a tapistry on the wall. It has a single window. There is also a small door hidden behind a dresser, behind which is a staircase that leads to the Trøg tunnels under the castle.
After Zøg took Jasper with him to the castle, Derek was forced to share his room with him.
It is unknown what became of the room after Derek left with Oona to become a pirate.