Haunted prisons exist around the world, which is one reason why the theme is often used in haunted houses. Prisons are scary to others because they try to imagine the people who once lived there and what they did that landed them behind bars. When you put together the right decorations, any space can become a haunted prison. Use Halloween prison decorating ideas to make one haunted room in your house or create a large scale haunted house, in any space imaginable.
For larger space, trace the roots of prisons, with each room symbolising a different era in criminal history. Use mannequins, with a few actors, to show different things the prisoners faced. Tell guests about the old days, when lynchings and drawing and quartering a person, were commonly accepted punishments for criminals. Show horse thieves, with one ear stuck to a wooden post with a nail, which was a punishment used for their crime. Line fake jail cell bars, with fake spider webs and use only minimal lighting in the room. You can scare guests even further by keeping one actor "locked" in a cell. Have the actor pretend to be a guest, who wandered away from his group.
Turn several rooms into a haunted prison asylum. Before taking guests on a tour, tell them that the space was used for the criminally insane prisoners and that some prisoners, died as a result of their treatment. Make one room the electroshock room, complete with a doctor in a white coat and a prisoner strapped down to a table. Electrodes strapped to the person's chest complete the look. When you lead a new group through, have the doctor throw the switch and the actor convulse on the table. Create other rooms, including a water bath room and a padded jail cell.
A haunted cell
For smaller spaces, create just one haunted cell. Make the cell as dark and spooky as possible, with fake spider webs and only a cot in the room. Use a few realistic looking rats in one corner of the room, complete with fake blood, which lets guests guess what the rats are chewing on. Up the thrills by having an actor jump out from underneath the bed. Alternatively, drape the walls in sheets of grey and have an actor in light grey clothing standing against one wall. He remains practically hidden, until the guests get close enough.