The Rehn system resided within the Brak sector of the Expansion Region. It contained the planet known as Rehn VII, which possessed the ability to produce foodstuff and had some manufacturing aptitude.
During the time of the Galactic Civil War, the Galactic Empire chose the system to serve as a forward operating base for the Imperial Navy. Due to the new security protocols, one needed proper authorization to enter the Rehn system. Strict enforcement resulted in severe punishments for unauthorized entrants. The system's perimeter was guarded by picket ships in conjunction with sensor installations.
Regardless of the Imperial Navy's attempts, the Alliance to Restore the Republic's Brak Sector Force successfully set up a listening post located on Rehn VII.