The White Towers were three tall towers located in the Emyn Beraid west of the Shire. The westernmost tower, called Elostirion, had a palantír which looked ever westward towards Valinor. The Shire-hobbits could see them shining far off in the moonlight; they said that from the top of Elostirion one could view the Sea.
The White Towers were built on the Emyn Beraid by Gil-galad as a gift to Elendil, perhaps after the founding of Arnor (S.A. 3320).
They were sometimes the destination of pilgrimage by Wandering Companies of Elves who would gaze to Valinor through the palantír. Such a band, led by Gildor Inglorion, met Frodo, Sam, and Pippin in the Woody End of the Shire on 24 September T.A. 3018.
With time, the Shire-hobbits grew estranged from the Elves and the concept of the Sea became a word of terror and death, and they avoided looking upon the towers on the west.
In September 3021 the Last Riding of the Keepers of the Rings, including Frodo and Sam, passed the White Towers on their way to the Grey Havens.