Thornhold is a coastal fortress, a castle of gray stone with a thick, curved wall and a two-towered central keep on the southern tip of the Mere of Dead Men. The cliff facing the sea is so sheer and smooth that no wall need be built on the side of the hill where Thornhold sits. The castle is without adornment; only crenellations and arrow slits break its solid face of stone. Inside the walls, surrounding the bailey, are small buildings of wood and plaster that house animals and are used for smithwork, candlemaking, gemcutting, repairing wooden items (including wagons and the like), and brewing beer. Thornhold was once the property of the Margaster family of Waterdeep and has been held by the Knights of Samular (paladins of Tyr) and the Zhentarim in the past. Its current occupants are the shield dwarves of the Stoneshaft clan. They refer to the castle as Stoneshaft Hold. The Stoneshaft dwarves are reclusive and secretive, yet they are interested to hear what’s afoot in Waterdeep, for they suspect the Margaster family is plotting to attack the fortress and reclaim its ancestral holding. Travelers are free to visit Thornhold, up to a point. The Stoneshaft dwarves allow adventurers and caravans to make camp within their walls, but they forbid access to the keep and the extensive caves below. Thornhold is rumored to contain a passage to the Underdark—a claim that the dwarves neither confirm nor deny.