Hogwarts secret passages


 * A passage beneath the Whomping Willow, leading to the Shrieking Shack.
 * A passage behind a mirror on the fourth floor, which is caved in. It leads to Hogsmeade, but where in Hogsmeade it leads to is unknown. Sirius mentions in book five that it is large enough for an organisation.
 * A passage beneath a one-eyed witch statue by the stairs to the Defence Against the Dark Arts, leading to the cellar of Honeydukes. Speaking aloud the word ‘Dissendium’ to the witch accesses this passage, the hump on the statue then opens and reveals the hidden passageway.
 * A link between two vanishing cabinets, one in the school and the other in Borgin and Burkes in Knockturn Alley. This link presumably worked until Chamber of Secrets when Peeves (persuaded by Nearly Headless Nick) smashed the Hogwarts cabinet. The passage was reopened in Half-Blood Prince when Draco Malfoy fixed the cabinet. This passage is not shown on the Marauder's Map.
 * A passage in the Room of Requirement, leading to the Hog's Head bar, however due to the nature of the Room of Requirement, it is possible that several passages to different locations could be accessed from it. This passage is created in Deathly Hallows and is therefore not shown on the Marauder's Map.