Dragonstone is a castle located on the island of the same name at the entrance to Blackwater Bay. Located below the Dragonmont and shaped from stone to look like dragons, Dragonstone was the original seat of House Targaryen in Westeros, and had been colonized and fortified as the westernmost outpost of the Valyrian Freehold. The castle has a dark reputation.
After Aegon's Conquest of the Seven Kingdoms, Dragonstone in the newly-created crownlands served as the seat of their heir apparent, known as the Prince of Dragonstone. The current Prince of Dragonstone is Baelon Targaryen.
Dragonstone, though old and strong, commands the allegiance of only a few lesser lords whose islands are too thinly populated to provide any great numbers of troops, although they have some naval strength. A short distance west of Dragonstone is the island of Driftmark, which is the seat of House Velaryon, a Valyrian house and historically a naval power. Other houses sworn to Dragonstone include Celtigar of Claw Isle, who are also of Valyrian descent, Seaworth of Cape Wrath, Bar Emmon of Sharp Point, and Sunglass of Sweetport Sound.