Harry used the map throughout his time as a student at Hogwarts, especially during his third year, when he tried to find his way into Hogsmeade. [1] Then, he used the One-Eyed Witch Passage which led into the Honeydukes cellar. Professor Remus Lupin caught Harry with the map (after Snape found it while interrogating Harry), and subsequently confiscated it, surprising the younger wizard with his knowledge of how to activate it. [12] In the film adaptation of Harry Potter and the Prisoner of Azkaban, Moony is misspelled "Mooney" as an inside joke to the film's visual effects supervisor, Karl Mooney.

It is unknown if the map shows deceased people. However, as Lupin was surprised at Pettigrew being on it when he believed him to be dead, it would suggest not. However, it is possible that the name Marauder was not meant to refer specifically to the group who created it, but rather it was a title or descriptor for one who uses it or for whom it was intended. Regardless, the name is generally taken to mean the former. To hide the contents of the map so the parchment appeared blank again, one would again tap it and recite, " Mischief managed." The Marauder's Map was a magical document that revealed all of Hogwarts School of Witchcraft and Wizardry. Not only did it show every classroom, every hallway, and every corner of the castle, but it also showed every inch of the grounds, as well as all the secret passages that were hidden within its walls and the location of every person in the grounds, portrayed by a dot. [1] It was also capable of accurately identifying each person, and was not fooled by animagi, Polyjuice Potions, or Invisibility Cloaks; even the Hogwarts ghosts or Peeves were not exempt. Also during end credits, in one of the corners in the castle as an Easter Egg, there appears two feet belonging to two students who are either hugging or kissing.One of the map's possible flaws was that it did not differentiate people who had matching names (the shared names were not given a Junior or Senior at the end). Also, it did not seem to show unplottable rooms, as it was Dobby and not the map that revealed the existence and location of the Room of Requirement.

During Harry's sixth year, he used the map often when he spent a great deal of time obsessing over Draco Malfoy's daily activities. When monitoring Draco Malfoy, Harry found he often disappeared off the map. [17] The cause of this was not revealed until after he asked Dobby to trail Draco to find out what he was doing when he disappeared off the map. Dobby discovered that Draco was disappearing into the Room of Requirement, which was not on the Marauder's Map. [18] Whether because it was Unplottable or the Marauders never found the room is unspecified. As Fred and George Weasley stole the map from Filch's office in their first year, it had to be returned there by, at the very latest, June 1990. While on the run in looking for Horcruxes, Harry would often look at the map to see what Ginny Weasley, his love interest, was doing, which would hint that the map works from any location. [19] This little beauty's taught us more than all the teachers in this school." — Fred Weasley regarding the Marauder's Map [src] The map was normally disguised as a blank piece of parchment. To view the map, one would tap it with one's wand and recite, " I solemnly swear that I am up to no good." The content of the map would then reveal itself. [1]

The Marauder's Map, along with his wand and the Cloak of Invisibility, is Harry's only remaining treasure from his time at Hogwarts. George Weasley: " This, Harry, is the secret of our success." Fred Weasley: " It’s a wrench, giving it to you, but we decided last night, your need’s greater than ours." George Weasley: " Anyway, we know it by heart. We bequeath it to you. We don’t really need it anymore." Harry Potter: " And what do I need with a bit of old parchment?" — Fred and George Weasley giving Harry Potter the map [src] While Hogwarts Castle is located on a large mountain in the films and video games, the map used as prop still shows the Castle on level ground. In this, and in most other aspects, the design of the map's cover might be based on an illustration depicting the city of Jerusalem in the 1485 Cologne edition of the Christian exegetical book "Postille" by Nikolaus of Lyra.