The King of the Hightower (feminine equivalent being Queen of the Hightower), was the ruler of Oldtown, which is now part of The Reach. The monarch of Oldtown resided in The Hightower.

The Kingdom of Oldtown was later united as Kingdom of the Reach, under House Gardener.

In the books

King of the High Tower is an ancient title held by the head of House Hightower dating back to the time they ruled their own independent kingdom. The title was abandoned when House Hightower was brought under the rule of the King of the Reach as part of a marriage alliance.