Within a valley enclosed by the mountains north of Fahrnor lies Tangledoom, a dense, secluded forest whose paths are prowled by evil ents and other menacing creatures. The surrounding mountains offer no easy passes in or out, but careful adventurers can reach the forest by venturing through the caverns underneath the nearby stronghold of Kahr-Dur. The only other visitors to the forest tend to be devotees of demonic cults that occasionally perform rituals in or near an ancient, subterranean demonic temple at the eastern end of the valley.

Throughout the valley grow patches of Kingswort, a thorny, yellow-leafed plant used in the preparation of certain magical potions and spells.