The Boathouse is an underground harbour at Hogwarts where the boats are stored and where they dock when the first years arrive at Hogwarts Castle every 1 September. Up until 1995 a portrait of Percival Pratt hung on one of the walls, concealing a shortcut to the Grand Staircase. There are some rafters in the ceiling, that are used to store the small wooden boats.

After Pratt's portrait was taken away from the Boathouse, there were only three entrances to this building: The path outside The Quad, the stairs going down from the Entrance Courtyard and the Lake.