Alnwick Castle is north of NewcastleGateshead in Northumberland and is one of the largest castles in England. It’s home to the Duke and Duchess of Northumberland as well as some of the greatest wizards in history! The castle was used as Hogwarts in the filming of Harry Potter. Geordie translation: Just up from the Toon, Alnwick Castle is a canny size. It’s yhem to royalty and even Harry Potter!