Castle Frankenstein is a stock setting in adaptations of Mary Shelley's Frankenstein or the Modern Prometheus. It is the gothic dwelling where Victor Frankenstein performeds his experiments and creates his infamous monster. However, there is no such place within the text of Mary Shelley’s original novel, where Frankenstein’s experiments take place in an apartment.
In real life, there is a Castle Frankenstein in the Odenwald mountain range near Darmstadt, Germany. Shelley may have chosen the name from this castle, though it is doubtful she ever visited.
The fictional Castle Frankenstein first appeared in the 1931 film, and its general appearance has been the basis for numerous imitations and spoofs.