What is the name of the magical map that shows everyone's location at Hogwarts?

The magical map that shows people’s locations throughout Hogwarts is the Marauder’s Map. When activated with the words “I solemnly swear that I am up to no good,” it displays the castle’s rooms, corridors, secret passages, and the names of people moving through them.

The map was created during their Hogwarts years by James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew. They used the nicknames Prongs, Padfoot, Moony, and Wormtail, collectively calling themselves the Marauders. Their knowledge of secret routes helped them explore the castle and sneak out after hours.

Fred and George Weasley stole the map from Filch’s office and later gave it to Harry. It is not completely infallible: magical concealment, unusual spaces, and certain powerful enchantments can limit what it reveals. A famous example is Peter Pettigrew, whose true identity appears on the map while he is disguised as Ron’s rat, Scabbers.