The Gorlan system was a star system that lay within the sphere of influence of the fallen Terran Empire. Located within were Gorlan Station and the planet Gorlan, home to the species of the same name.
In the 23rd century the Gorlan rebelled against the empire. They were presumably wiped out when James T. Kirk, in one of his first acts as captain of the ISS Enterprise (NCC-1701), destroyed their homeworld to suppress their uprising. (TOS: "Mirror, Mirror")