In the seventh book, Harry wonders if 'the trace' is still on him after his seventeenth birthday, as the Ministry of Magic/Death Eaters keep managing to track him, Hermione and Ron down. It is later revealed that Voldemort's name has been "tabooed", so that the location of anyone speaking it will be revealed, and the

However, in the first book, 'the trace' would only have worked if Harry was using magic- which, aside from setting a Boa Constrictor on Dudley, does not happen. The address(es) on the Hogwarts acceptance letter(s) sent to Harry are very specific:

"Mr H. Potter, The Cupboard under the Stairs, 4 Privet Drive, Little Whinging, Surrey"

"Mr H. Potter, The Smallest bedroom, 4 Privet Drive, Little Whinging, Surrey"

"Mr H. Potter, Room 17, Railview Hotel, Cokeworth"

At first I thought that the Anthony Horowitz book "Groosham Grange" (which was published a decade before Harry Potter and JK cited as an influential resource) might help provide an answer, as in the book a black crow is sent by the school to watch David. However, there are no mentions of Owls/other birds except for the ones delivering the (already addressed) mail.

It's possible that professor Trelawney used a crystal ball or her prophecy powers to watch Harry's movements, however, in 'The Prisoner of Azkaban', Dumbledore comments:

'Do you know, Harry, I think she might have been,' he said thoughtfully. 'Who'd have thought it? That brings her total of real predictions up to two. I should offer her a pay rise…' (PA22)"

As her first real prediction was the prophecy "neither shall live while the other survives", and the second was the one about "the servant returning to his master". Crystal-ball-gazing doesn't seem to extend to present events as such, and in any case, Dumbledore admitted in the quote that she wasn't a great seer, so what I'm wondering is:

How did the Hogwarts professors know (and in such great detail) where Harry was, and; Why couldn't this method be replicated in later books (such as when the Death Eaters wanted to track Harry)?

Additionally, does anyone have any idea how (Wizarding-world) Owls can manage to track people with no addresses written on them? E.g, in book 4, (aside from being a super-smart bird) how is it that Hedwig can easily find where Sirius is?

  • 4
    My impression of that first book's sequence is that either Hagrid was following them, or given Hagrid's lack of wizardry, Dumbledore was and simply sent in Hagrid once they'd gotten to the extreme absurdity point.
    – Radhil
    Commented Sep 14, 2015 at 17:50
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    My guess is that owls are able to find people. Remember an owl from the Daily Prophet delivered a paper to Hagrid at the Hut on the Sea. The letter were probably magically adressed and automatically picked up by the owls to deliver.
    – Tdmut
    Commented Sep 14, 2015 at 21:30
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    Perhaps for those students-to-be the magical quill that identifies them also tracks them and knows where they are? And stops once they're safely on role?
    – ThruGog
    Commented Sep 14, 2015 at 21:55
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    great question! Commented Sep 17, 2015 at 16:16
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    Should be noted that wizards can make themselves ‘unplottable’ so it’s not as simple as that. Not saying it’s relevant to Harry though.
    – Pryftan
    Commented May 13, 2018 at 21:06

3 Answers 3


There is no direct canon information, but we have enough circumstantial evidence:

  1. In general, the Hogwarts invitation letter comes to the correct address of any student. People (Muggles and Wizards) do move, therefore there must be a generic mechanism to deliver those letters to correct address.

  2. There is magic that allows one to see where someone is (it was used in making the Marauder's Map). Therefore, a spell to do #1 is clearly feasible in-universe.

    • Also, we know of other "auto-finder" magic in-universe: owls (Sirius' letters from Harry); Patronuses (as used for communication by the Order); Deluminator (tracked Harry and Hermione for Ron); Taboo spell (homes in on whoever said the V word where they are).

A far less plausible, yet possible, alternate theory is that this was Dumbledore messing with Dursley's heads.

  • 1
    I fully agree with OP's assertion that, owing to exact addresses printed in PS, this was NOT related to owl's address-finder feature. Commented Sep 17, 2015 at 16:17
  • you've been answering a lot of my questions on stack sci/fan recently; here, have an upvote :3
    – Mikasa
    Commented Sep 18, 2015 at 14:45
  • what's the crazy theory about head-messing? XD
    – Mikasa
    Commented Sep 18, 2015 at 16:03
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    @MikasaPinata He's been answering so many that your upvote doesn't get him any rep, since he's hit his daily max!
    – Rand al'Thor
    Commented Sep 18, 2015 at 16:21

Although I really like DVK's answer, I think it's more mundane then that. We know that the Good guys have been watching over Harry from a distance (and in animal form as well) his entire childhood. I am sure, after watching him for 11 years they were able to suss that his room is in "the cupboard under the stairs".

  • Yes, McGanagoll the tabby, mrs Figg and others. And also various kinds of location magic mentioned above and more, like the Weasley's crazy clock.
    – user68762
    Commented Aug 9, 2016 at 23:13
  • +1 I think mrs Figgs is defiantly the most likely and was my first thought. Its implied Harry visited her and that she was on good terms with the Dursleys, (she even apologized to Harry for being mean to him because it was the only way the Dursleys would let her see him). Its highly likely she talked with & visited the Dursleys house, its also likely Harry himself talked to her on several occasions (otherwise why would she apologize)
    – Matt
    Commented Oct 11, 2017 at 16:38

There is no specific information, but there are other instances in the books when magic is used to locate a person.

  1. Dumbledore locating Tom Riddle, Hermione Granger, or any other wizard living in a muggle environment.

  2. The Marauder's Map. Considering the fact that the marauders were in their school years when creating it, the charm used on it (Homonculous Charm) was probably not too advanced. If there's a way to locate a person's exact location on a map, there is most likely a way to find out Harry lives in a cupboard, then Dudley's old room, then the hotel, then the rock, and so on.

In conclusion, every wizard (and presumably muggle) is locatable, unless a spell or an artifact was used to hide said wizard.

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