"Bet it's that one behind the statue of Gregory the Smarmy that we found in our first week. See you."
-- Fred Weasley, on the secret passageway Lee Jordan claimed to have discovered (PS9)
Secret passages are everywhere in such an old and magical place as Hogwarts; they are concealed in a variety of ways but many have been discovered by more rebellious students such as the Marauders and the Weasley twins, as well as Filch.
- Behind the statue of Gregory the Smarmy on a fifth floor corridor of the east wing (PS9, OP29, OP30). Filch knows about this passage; Fred and George found it in their first week at Hogwarts (PS9, PA10)
- Three other passages leading out of the school that Filch knows about (PA10)
- Under the hump of the statue of the hump-backed witch, leading to Honeydukes' cellar (PA10)
- Under the Whomping Willow, leading to the Shrieking Shack (PA10)
- Behind a mirror on the fourth floor; caved in in the winter of Harry's second year (PA10). Sirius suggested that the D.A. could meet there, but Harry informed him that it was unusable (OP17).
Other passageways offer shortcuts around Hogwarts Castle. Tapestries on the walls of the corridors sometimes hide them (PS9, CS8, OP28, HBP14), including the entrance to the staircase with the trick step (GF12, GF25). A statue located between Gryffindor Tower and the Owlery, requiring a left turn from the common room to find, may also hide a passage; Mrs. Norris disappeared behind this statue while setting out to report to Filch after encountering Harry on his way to the Owlery (OP14).