Onthrilaenthor was a ruined Eaerlanni settlement in the eastern Star Mounts. It was created for the elves by the Ammarindar dwarves and consisted of miles of tunnels and chambers cut into the rock, including vertical shafts to an area near the summit of the southern Star Mounts. The presence of stables near this shaft led to the belief that it was used by the Eaerlanni elves for aerial mounts. Onthrilaenthor was affected by strong winds, sometimes making it difficult to walk through the tunnels.