Não está claro.

Nos livros, nunca recebemos um indicador claro de onde ela mora, mas dos filmes que ela mora em Hampstead, Londres.

Now’s your chance to live like Hermione Granger—during summer vacation from Hogwarts, anyway. The house used as Emma Watson’s teenage witch’s family home in Harry Potter and the Deathly Hallows: Part 1 is up for sale for the first time in sixty years, according to the listing. Situated in a cul-de-sac in the northern London suburb of Hampstead, it’s a spacious three-level, six-bedroom home with a classic, verdant back garden; you can just imagine the fictional dentists Mr. and Mrs. Granger raising their super-studious daughter Hermione in the light-filled living room.
_{- You Can Now Live in Hermione Granger's House from the Harry Potter Movies - Time}

Então, se devemos confiar nos filmes; ela morava em Hampstead, mas fora isso, não há menção de onde ela mora (nos livros).