Devil's Castle

Dracula's Castle (ドラキュラ城 Dorakyura Jō?), also known as Devil's Castle (悪魔城 Akumajō?) or Castlevania, is Count Dracula's lair and symbol of his magic. It houses an army of his supernatural minions, and tends to collapse when Dracula is defeated. Yet, it is able to restore itself and reappears intact.
The exact location of the castle is impossible to determine. Being an entity of Chaos, it has the ability to reemerge in different places whenever it revives. Still, the vast majority of times it has reappeared was in Europe, in Transylvania.
If one takes into account the events from the original 1897 novel that inspired the series, as well as real historical landmarks where Vlad III Drăculea was known to inhabit, that may be indication that the castle from the series was at some point located somewhere in Transylvania or in northern Wallachia, where one of the voivode's real castles, Cetatea Poenari, is located.