Location from Curse of Strahd by Tracy & Laura Hickman, Chris Perkins / Wizards of the Coast
The vast catacombs beneath Castle Ravenloft, holding the remains of the von Zarovich family and their servants — Strahd's coffin rests here.
The crypts beneath Castle Ravenloft are extensive — row upon row of stone sarcophagi and sealed tombs, each bearing the name and epitaph of someone who served or belonged to the von Zarovich line. The air is cold and still, and the only light comes from whatever the intruder brings. Strahd's coffin is here, and it is where he retreats when reduced to mist. Destroying the coffin or filling it with holy water is one of the few ways to prevent his regeneration. Sergei's tomb is also here, containing his blessed armor. Other crypts hold traps, treasure, and things that should have stayed buried. The crypts are the final battleground. When adventurers come for Strahd at last, this is where it ends.
Also known as: the crypts, Ravenloft crypts, the catacombs