Well, there can be many factors of why the terrain is still incognita, (Not only in this story but in the real world too)The climate is and/or terrain is to harsh to be explored, (which you will see is the case)Exploring certain areas would be too costly, in manpower, money or even equipement.And finally, it could be another nation's land.Equestria isn't technologically advanced enough to allow yet colonies so far up north. It's beyond high mountains and the cold over there is extreme. It's further away than the actual Crystal Empire, and I doesn't yet exist. Fast transportation doesn't exist yet, and even if pegasus can fly, the frost would prevent them from doing it.I hope this explains a bit(and I don't want to spoil too much, I'd like that for some things, the readers would imagine it. This comic settles in a period so old, that many books, illustrations, history just vanished. This is all my perspective of things, and even if it's not really perfect, and maybe crappy in some ways and/or some places, I still like itTime and ressource is what I'm missing right now to really tell my story. I don't have much time to write all my ideas, I just draw them, and forget them quickly.But anyway, I hope you enjoy this story so far, and that you will appreciate it 'til the end!(sorry for the little rant)