Unplottable Charm

• Incantation: None known. This is a complex enchantment rather than a spell cast with a single, simple incantation.
• Pronunciation: N/A
• Wand Movement: None known.
• Light: None described.
• Effect: Renders a specific building or area impossible to be plotted or located on any kind of map, including both Muggle and magical maps like the Marauder's Map. To a person viewing a map of the region, the Unplottable location will simply not appear, often leaving a blank space where it should be.
• Type: Charm (Defensive/Concealment)

The Unplottable Charm is a powerful and complex piece of magic used to hide significant wizarding locations. Its primary function is to prevent a location from being discovered via cartography. Several key places in the wizarding world are protected by this charm.

• Hogwarts School of Witchcraft and Wizardry: Hermione Granger explained to Harry Potter and Ron Weasley that Hogwarts is Unplottable. This is one of the school's most fundamental protective enchantments, preventing anyone from mapping its location. This is why students from other schools like Beauxbatons Academy of Magic and Durmstrang Institute had to be given directions to the school for the Triwizard Tournament.
• Quidditch World Cup Campsite (1994): The massive campsite set up for the 1994 Quidditch World Cup was made Unplottable to prevent the hundreds of thousands of attending witches and wizards from being discovered by Muggle authorities.
• Number Twelve, Grimmauld Place: The ancestral home of the Black Family and the headquarters for the Order of the Phoenix was made Unplottable. This was an added layer of security on top of the much more powerful Fidelius Charm that protected the house. While the Fidelius Charm hid the house's very existence from those not told the secret, the Unplottable Charm ensured it could never be marked on a map, even by wizards.
• Foreign Wizarding Schools: Hermione Granger mentioned that other major wizarding schools are also Unplottable, as their locations are closely guarded secrets.
• Room of Requirement: In its “Room of Hidden Things” configuration, the Room of Requirement becomes Unplottable on the Marauder's Map. Harry Potter discovered this in his sixth year when he was unable to locate Draco Malfoy on the map, realizing that the map did not show the room.

Casting the Unplottable Charm is considered to be very advanced magic. It is not part of the standard Hogwarts curriculum and is only known to be used by powerful witches and wizards for high-level security. There is no known counter-spell to directly remove an Unplottable Charm. However, the charm has a significant limitation: it only prevents a location from being mapped. It does not make the location invisible, intangible, or prevent it from being stumbled upon by accident. For this reason, Unplottable locations often require additional layers of protection.

• Muggle-Repelling Charms: These are often used in conjunction with the Unplottable Charm at locations like Hogwarts and the Quidditch World Cup campsite. While Muggles cannot find the location on a map, these additional charms are needed to divert any who might wander into the area by chance.
• Fidelius Charm: For maximum security, the Unplottable Charm can be combined with the Fidelius Charm. The Unplottable Charm prevents mapping, while the Fidelius Charm magically conceals the location itself, making it impossible to find unless the Secret-Keeper reveals its location.

The name is derived directly from English. The prefix “un-” means “not,” and “plottable” means “capable of being plotted or marked on a map or chart.” The name is a literal description of the charm's effect: to make something “not able to be mapped.”

The Unplottable Charm is a canonical magical concept from the original seven novels. J.K. Rowling has not provided any further details about its incantation or specific casting method on Pottermore or in interviews. The concept is maintained in the film adaptations, where locations like Hogwarts and Number Twelve, Grimmauld Place are shown to be magically concealed from the outside world.