The Ayai'leh-hirh range is the largest mountain range on the planet Trill, and one of the largest on any inhabited planet known to Federation scientists as of the 2370s. In English, the name of the range translates to Five Thousand Valleys. Mountains in the range include Arken, Ilrienh, Noraikghe, Oraidhe, and Sethe. (TNG novel: Intellivore) In 2376, Ezri Dax saw the peaks of Ayai'leh-hirh in the distance as she piloted the USS Rio Grande towards the Caves of Mak'ala. (DS9 - Worlds of DS9 novel: Trill: Unjoined)