Sandstone

Sandstone is a castle in Game of Thrones. It is a holdfast in Dorne, the region controlled by House Martell of Sunspear. The castle is located in the south west of Dorne west of the Brimstone. It is near Hellholt.

In the books
In the Song of Ice and Fire novels Sandstone is the seat of House Qorgyle. Its location is the same.