- "Yonder are the Thrihyrne peaks like black spears. It will not be long before we reach the branching roads to the Deeping-Coomb, where the battle was fought two nights ago."
- —The Two Towers, "The Palantir"
Thrihyrne refers to the three steep-sided mountains that stood out above the gorge of Helm's Deep. They were the northernmost of the White Mountains , and so they also marked the southern edge of the wide Gap of Rohan. Gandalf showed these mountains to Pippin when they were escaping the eyes of a Nazgûl on Shadowfax, while returning from Isengard.
'Thrihyrne' is an Old English name and means simply 'three horns'.