A map showing the location of Tarth off the coast of Westeros.
Tarth is an island in the Narrow Sea off the south-eastern coast of Westeros, separated from the mainland by the Straits of Tarth. It is part of the Stormlands and is held by House Tarth, vassals of the Baratheons.
The Tarth castle, located on the west coast of the island, is called Evenfall Hall. It is the home of Brienne, sometimes called the Maid of Tarth.
In the books
In the Song of Ice and Fire novels, Tarth is said to be a beautiful island. It is called the Isle of Sapphires for the clear blue waters surrounding the island. The island contains mountains, waterfalls, high meadows and shadowed vales.