The Dungeon Corridor was a long, gloomy stone corridor that led from the narrow spiral staircase, coming down from the Viaduct Entrance, to the staircase leading down to the blank stone wall which was the entrance to the Slytherin Dungeon. The Potions Classroom, and possibly Severus Snape's office, could be found along this corridor, as well as some cells. The Slytherin Corridors were probably adjacent to this corridor.