Muggle-Repelling Charms

• Incantation: Unknown. This is likely a general term for a category of enchantments rather than a single spell with one specific incantation.
• Pronunciation: Not applicable.
• Wand Movement: Unknown.
• Light: The casting of the charm produces no visible light or effect that is described in the novels.
• Effect: Causes a non-magical person (Muggle) who approaches an enchanted area to suddenly recall an urgent, forgotten appointment. This compels them to turn back and leave the location without arousing their suspicion or making them aware of the magic at work. To a Muggle, the protected location may also appear as something mundane, uninteresting, or dangerous, such as a derelict building or ruin.
• Type: Charm

Muggle-Repelling Charms are a fundamental type of magic used by the wizarding community to conceal magical locations and events, thereby helping to maintain the International Statute of Secrecy.

• Hogwarts School of Witchcraft and Wizardry: The school and its grounds are protected by countless ancient enchantments, including powerful Muggle-Repelling Charms. As mentioned in the book A History, if a Muggle were to look at the castle, they would not see a school but rather a moldering old ruin with a sign over the entrance that reads, “DANGER, DO NOT ENTER, UNSAFE”.
• 1994 Quidditch World Cup: The Ministry of Magic used these charms on a massive scale to hide the tournament's campsite from Muggles. Arthur Weasley explained to Harry Potter that hundreds of Ministry wizards had been working for months to place Muggle-Repelling Charms over the entire moorland area.
• St Mungo's Hospital for Magical Maladies and Injuries: The magical hospital, located in London, is concealed behind the facade of a closed-down department store called Purge and Dowse, Ltd. The enchantments on the building ensure that Muggles pay it no attention whatsoever, walking past without a second glance.
• The Hunt for Horcruxes: During their mission to find and destroy Lord Voldemort's Horcruxes in 1997-1998, Hermione Granger regularly cast Muggle-Repelling Charms around their tent each time they set up camp. This was a crucial part of their daily defensive enchantments, used alongside other protective spells like Protego Totalum, Salvio Hexia, and Cave Inimicum to keep them hidden from both Muggles and Death Eaters.

• Learning: The difficulty of mastering these charms is not explicitly stated. However, Hermione Granger's ability to cast them effectively and repeatedly under pressure suggests that they are learnable by a skilled and knowledgeable student. Their widespread use by the Ministry of Magic indicates they are standard for officially sanctioned concealment efforts.
• Counter-Spells: There are no known counter-spells. As the charms specifically target the minds of non-magical people, a witch or wizard is not affected by them and therefore does not require a counter-spell to enter a protected area. The enchantments are perceptual and psychological, not physical barriers.

The name is purely descriptive and functional. It combines “Muggle,” the established term for a non-magical person in the British wizarding world, with “repel,” which means to drive or force back.

There is no additional information about the specific origins or mechanics of Muggle-Repelling Charms from J.K. Rowling's interviews or on the Pottermore/Wizarding World website beyond what is described in the original seven novels. The concept is a foundational element of world-building that logically explains how major magical institutions and events can remain hidden in the modern world.