Harrenhal, the largest castle in the Seven Kingdoms, is the seat of House Targaryen of Harrenhal in the Riverlands, on the north shore of the Gods Eye lake. Since its burning by dragonfire in the War of Conquest, however, it has become a dark and ruinous place.
The castle's holdings are some of the richest in Westeros, claiming vast tracts of green fertile land which reach as far as the hills of House Wode near the crownlands. Harrentown is found near Harrenhal.
The castle has five towers of dizzying size, with equally monstrous curtain walls. The walls are incredibly thick and its rooms are built on a scale that would be more comfortable for giants than humans.
Harrenhal covers three times as much ground as Winterfell and its buildings are so much larger that they can scarcely be compared. Its stables can house a thousand horses, its godswood covers twenty acres, and its kitchens are as large as Winterfell's Great Hall.
However, much of Harrenhal has far gone into decay. The Whents use only the lower thirds of two of the five towers, letting the rest go to ruin, and many places in the castle have not been entered in decades. Bats infest the tops of some of the towers.