Guide:
Northeastern Cyrodiil, just west of Kingscrest Keep.
Skyshard is situated in Sedor Ayleid Ruins. You should look for a small stone wall, one tall stone arch and one wrecked arch to lead you to this location. There might be couple of enemies defending the main part of ruins, where our collectible is at. Approach this part of Ruins from the northeast. Keep hugging the wall. This way you will not pull the nearby enemies. Sedor Ayleid Ruins is really close to a nearby main road. If you are part of a faction that doesn’t hold the nearby keep, you should be more aware of hostile players. This area is really close to The Ebonheart Pact starting Cyrodiil position.