We all know that dawngaurd takes place in skyrim but where?! Like where is fort dawngaurd?

its invisible so we dont know where it is yet, duh

It will probably be quest related that brings you to this amazing place! Definitely won't be on your map, good luck!

Third star to the right & straight on till morning.

Well from the trailers we can assume that Dawnguard Castle is in Riften and that the vampiric fortress is in the northern glaciers but that's my thoughts but it could be outside the map in another location but I think it's unlikely.

Or maybe the north star near never never land.