The King's Tower is one of the towers at Castle Black. It is reserved for honored guests. Though named for kings, no king has visited the tower in over a hundred years. It is a round tower with merlons atop it and has an oak door studded with iron.
A Game of Thrones
Tyrion Lannister stays in the King's Tower when he visits Castle Black. Lord Commander Jeor Mormont moves his quarters to the King's Tower after the Lord Commander's Tower burns down.
A Storm of Swords
Jon Snow, Satin, and Dick Follard defend the tower against the wildlings during the attack on Castle Black.
A Feast for Crows
Stannis Baratheon claims the King's Tower when he encamps along the Wall.