Hogwarts seems to house many ghosts but has it ever been mentioned in the narrative, of ghosts that reside outside the castle? At Beauxbatons and Durmstrang, for instance? Or at the Ministry? It's been a while since I read HP so I might have missed some obvious clues.
Rowena Ravenclaw/Grey Lady is one ghost I can think of who would have wanted to stay away from Hogwarts after running away with the diadem but she too returns back after her death. Though improbable, it lead me to believe that Hogwarts is the sole residence for ghosts until I came across this on Pottermore.
Hogwarts is the most heavily haunted dwelling place in Britain (and this is against stiff competition, as there are more reported ghost sightings/sensings on these damp islands than anywhere else in the world).
But I can't make sense of the above sentence. Stiff competition from whom? Also, "damp islands" as in Hogwarts?
This, of course, means that Hogwarts is the preferred dwelling place for ghosts despite not being the sole one right?
I couldn't find this question on here but if it's a duplicate, please do mention.