The Secret Passages of Hogwarts Castle

• Type: Network of concealed tunnels and shortcuts
• Location: Primarily within the grounds of Hogwarts Castle, with several connecting to the nearby village of Hogsmeade.
• Owner/Residents: The passages have no formal owners. They are known and used by a select few, most notably The Marauders, Fred Weasley, George Weasley, Harry Potter, and Argus Filch, who is aware of some of them.
• Key Features: Entrances are magically concealed behind objects like statues, mirrors, or trees. Access often requires a specific spell or physical action. The most comprehensive guide to these passages is the Marauder's Map.

The secret passages of Hogwarts Castle are a series of seven hidden routes that allow for clandestine travel within the castle and to and from Hogsmeade. Their existence is a closely guarded secret, unknown to the general student body and most of the faculty. The castle's caretaker, Argus Filch, knows of four of them but lacks the means to use them all. The definitive map of these passages was created by The Marauders—James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew—during their time at Hogwarts. Their creation, the Marauder's Map, shows the location of every passage and the people moving within them. The map was later confiscated by Argus Filch and subsequently stolen by Fred Weasley and George Weasley, who memorised its secrets. In their third year at Hogwarts, they gifted the map to Harry Potter, believing he had greater need of it. Over the years, some passages have become unusable. One was sealed by Argus Filch, and another caved in. During the Second Wizarding War, new passages were also created, such as the one connecting the Room of Requirement to the Hog's Head Inn, which was not documented on the original Marauder's Map.

The secret passages are instrumental throughout the series, providing crucial, unobserved access for main characters at key moments.

• In Harry Potter and the Prisoner of Azkaban, Harry Potter uses the passage behind the one-eyed witch statue to sneak into Hogsmeade after being denied permission. The passage beneath the Whomping Willow is central to the book's climax, serving as the route for Remus Lupin's transformations and later used by Harry Potter, Ron Weasley, Hermione Granger, and Sirius Black.
• In Harry Potter and the Half-Blood Prince, a unique form of passage is created by Draco Malfoy using a pair of Vanishing Cabinets. This allows him to bypass Hogwarts's formidable security and smuggle Death Eaters into the castle, leading directly to the death of Albus Dumbledore.
• In Harry Potter and the Deathly Hallows, a new passage connecting the Room of Requirement to the Hog's Head Inn becomes a vital lifeline for Dumbledore's Army. It is used to bring in food and supplies for the students hiding in the school and serves as the primary route for members of the Order of the Phoenix to enter the castle for the Battle of Hogwarts.

The Marauder's Map reveals seven secret passages, though not all are described in detail or remain usable.

1. The One-Eyed Witch Passage:
   • Entrance: The stone statue of a hump-backed, one-eyed witch on the third floor. It is opened by tapping the statue with a wand and speaking the incantation `Dissendium`.
   • Exit: The cellar of the Honeydukes sweetshop in Hogsmeade.
   • Notes: This is the passage Harry Potter used to visit Hogsmeade in his third year.
2. The Whomping Willow Passage:
   • Entrance: A small opening amongst the roots of the Whomping Willow on the Hogwarts grounds.
   • Activation: The tree must be temporarily paralysed by pressing a specific knot on its trunk.
   • Exit: The Shrieking Shack in Hogsmeade.
   • Notes: This passage was created to allow Remus Lupin to leave the castle grounds for his monthly transformations into a werewolf.
3. Passage Behind the Fourth-Floor Mirror:
   • Entrance: A large mirror on the fourth floor.
   • Exit: The passage supposedly led out of the school.
   • Notes: According to Fred Weasley and George Weasley, this passage had caved in and was completely blocked.
4. Passage Behind the Statue of Gregory the Smarmy:
   • Entrance: A statue of Gregory the Smarmy, located in a corridor forbidden to students in their first year.
   • Exit: Unknown, but it provides a shortcut to another part of the castle.
   • Notes: This was one of the passages frequently used by the Weasley twins for quick travel within Hogwarts.
5. The Vanishing Cabinet Passage:
   • Entrance: The Vanishing Cabinet located in the Room of Requirement.
   • Exit: Its twin cabinet, located in Borgin and Burkes in Knockturn Alley.
   • Notes: Not a true architectural passage, this route was established by Draco Malfoy in his sixth year. It is a magical transport link rather than a physical tunnel.
6. The Hog's Head Inn Passage:
   • Entrance: The Room of Requirement. The entrance changes location within the room as the room itself changes.
   • Exit: Behind the portrait of Ariana Dumbledore in the public room of the Hog's Head Inn.
   • Notes: This passage was seemingly created during the 1997-1998 school year. Because it did not exist when The Marauders created their map, it does not appear on it. It was revealed to Harry Potter by Neville Longbottom and Aberforth Dumbledore.
7. An Unspecified Blocked Passage:
   • Entrance: Unknown.
   • Exit: Unknown.
   • Notes: The Marauders noted on their map that this passage was blocked and had been sealed by Argus Filch.

• In the film adaptation of Harry Potter and the Prisoner of Azkaban, the one-eyed witch statue is shown to physically slide aside to reveal the passage, rather than requiring an incantation.
• In the video game version of Harry Potter and the Chamber of Secrets, a secret passage is found behind a statue of Gunhilda of Gorsemoor, which is a non-canon detail exclusive to the game (video game).
• J.K. Rowling has confirmed on Pottermore that there are seven secret passages at Hogwarts, consistent with the number shown on the Marauder's Map in the books (Pottermore).