The Crystal Empire
settlement (non-grifix) inside Frozen North
Can be home to characters.

After the Great Cataclysm:
The crystal academy
The Crystal Empire is a university center in Equestria and contains records of knowledge that has been saved from before the Great Cataclysm.
The university from the Crystal Empire is called the Crystal Academy, and its libraries hold almost all the world's knowledge between their walls. It is only, perhaps, the Frozen Empire's library that hold more knowledge than this.
The Crystal Academy also regulates most of the trades in the Empire, including the trades with the Frozen Empire.