The Outer Colonies were planets controlled by the Terran Confederacy. Despite a similar naming, they were a separate group of planets from the Fringe Worlds, but overlapped astrogeographically. For instance, Mar Sara was both a Fringe World and Outer Colony.
By 2478, revolts were common among the Outer Colonies and were steadily growing in number. By 2499, there is evidence that the Confederacy sought to discourage settlement of the Outer Colonies.