Guide:
Eastern Cyrodiil, between Farragut Keep (to the north) and Drakelowe Keep (to the south).
Skyshard is inside a public dungeon – Vahtacen. Entrance to this cave is at the most northern part of the river that goes through eastern Cyrodiil. Entrance of the cave is rather epic. Creatures inside come mostly in groups of two. Couple of them are well hidden behind cave corners. Be careful and don’t rush. If you are careful enough not to pull patrolling mobs, walking to the collectible location is going to be easy. Vahtacen’s skyshard is tucked in the most southwestern part of the cave.