From Ardrana

The region of Garnath was once an independent region located south of the eastern spur of the Onyl Mountains, between Alior to the west and Tyllan to the east. The region ceased to exist during the Wars of Arin, when its king, Ogre, was overthrown by Zathmore, and then Zathmore rebelled against the Onyx Empire and was himself deposed. Rule of the region was turned over to the drow general Daelras. Soon afterwards, Garnath was melded into Tanilon when the Onyx Empire conquered that land. Even today, there remains a dispute over whether the region is part of that land, or part of Arin itself.