The Haunted Hill Zone is a Zone on the Floating Island, exclusive to Sonic the Comic Online. Seemingly underground, the location is a rocky, inhospitable Zone, haunted by the ghosts of fallen Drakon soldiers of the Great War. A ghost train periodically runs through the Zone on a track.
Porker Lewis was taken here by Rouge the Bat, intent on interrogating him about how to open the box containing the Chaos Emeralds. Her plan was to use the Zone's ghosts to do the torturing for her. Knuckles the Echidna, Tikal, Big the Cat and Buddy followed them to the location and barely survived the derailment of the train.
The Zone is ruled by King Boom Boo (or the King of the Ghosts).
The Zone also made an appearance as Pumpkin Hill in Sonic Adventure 2, complete with ghosts and the train. It also combines several elements from the Death Chamber level, also haunted and containing hourglasses.