Star Wars: Dawn of Darkness
The Unknown Regions is a term that refers to the regions of space that remain mostly uncharted and are not connected to the web of known and reliable hyperspace routes that make travel throughout the remainder of the galaxy possible. The bulk of what is generally referred to as the Unknown Regions]] lies to the north west and sits adjacent to the Outer Rim Territories.
It has been theorized for millenia why the western most region of the galaxy is not connected to these hyperspace lanes and remains mostly uncharted to this day, but the reasons for which remain unknown even to the greatest minds of the Galactic Empire.
Encounters with the Player Party
The player party first learned of the need to travel to the Unknown Regions when they were wold of the loss of contact with the planet Bodir, deep in the Unknown Regions and accessible only by a secret hyperspace route kept by the Wookie refugees who settled on Dantooine.