This article is about the place. For the chapter see The Black Lake (chapter)Eagle Mountains, in the north of Prydain. Beneath its waters lay the Realm of the Fair Folk, a vast subterranean lair.
On their journey northward from Medwyn's Valley, Taran led the Companions over a difficult region of sheer rocks. He believed he could take a short cut around the shore of the Black Lake. By some enchantment the companions found themselves not only plunging into the water but dragged, inexorably, into its depths. They soon found themselves in an underground cave, whence they were taken by gruff warriors to an audience before King Eiddileg, "the Dwarf King" of the Fair Folk.