Three Towers

Three Towers is a castle in Game of Thrones. It is a holdfast in the Reach, the region controlled by House Tyrell of Highgarden. The castle is located south west of Highgarden and south west of Oldtown. It is on the southern side of the estuary of the river that flows past Oldtown and into the Redwyne Straits.

In the books
In the Song of Ice and Fire novels Three Towers is the seat of House Costayne. Its location is the same and the river is known as the Sound, with the estuary called the Whispering Sound.