Sarsfield

Sarsfield is a castle in the Westerlands, the region controlled by House Lannister of Casterly Rock. It is located southwest to Golden Tooth and northeast of Casterly Rock, being connected to the two castles through the River Roard, and northeast of Hornvale.

In the books
In the A Song of Ice and Fire novels, Sarsfield is the seat of House Sarsfield, a loyal vassal house of the Lannisters.