There is one behind (North of) Vengard. You can go through the woods behind the 3 trolls,as you are in Faring, towards the east until you reach the cliffs above Vengard and then to the North. Its guarded by Ogres but you can creep/run by them easily. Another way would be to be Guided to another pass by the Nordmarian warrior that is a prisoner of the orcs in Silden (also will net you a +2 rep in Normar). Do not let go of Ali's Stone, you are going to need it in Nordmar for a quest line…