where is Droknar's Forge?

I can't find it on the interactive map...

Southern part of the snowy mountains. It's not on the map because it's beyond the Crystal Desert in game terms.

The interactive map is a bit outdated...try this one.

It's down at the bottom of the Shiverpeaks, all the way south from Borlis Pass. You can either go there by doing all the missions until you Ascend, or take a shortcut through Lornar's Pass. However, the latter requires you to be well prepared before you start your journey south...