Three high Towers that rose from the hills known as Emyn Beraid, the Tower Hills, in the far west of Eriador. They were built by Gil-galad of Lindon for Elendil, and stood within the western borders of Arnor, the new land that Elendil founded in Middle-earth.

The tallest of the three White Towers, known as Elostirion, held one of the three palantíri of the North-kingdom, so attuned that Elendil could look through the Seeing-stone across the Great Sea into the lost West. This palantír remained in the Tower of Elostirion throughout the millennia of the Third Age, until it was returned to Aman aboard the White Ship.

Through most of the history of the Shire, the three Elf-towers were distant and mysterious buildings lying beyond the Hobbits' western borders. After the War of the Ring, however, the new King Elessar extended the western border of the Shire to create a new Westmarch that encompassed the White Towers on their Hills. From the year IV 31, then, the White Towers lay within the lands of the Shire-hobbits, and the new Wardens of Westmarch established themselves in the Tower Hills beneath the Towers themselves. Their new settlement was known as Undertowers, and would be important in the future history of the Shire and its people.