The Frontier is the outer region of the Terran Sphere. Numerous Frontier worlds, independent or new colonies, are outside of the established Terran hegemonies. Several inhabited alien worlds are also found here, ignored or untouched by Terran colonists. Some hinterlands nations such as the Star Kingdom of Rigel have assets on the frontier, but for most major nations the frontier is simply too far away and underdeveloped to be worth the costs of going there.

It should be noted that while the confederation of outlying systems was near the frontier when it was formed, it is one of the oldest major nations still in existance, and the frontier has long ago moved on.

As the Terran Sphere expands the Frontier expands with it. Given the overarching lack of big government on frontier worlds, the ever expanding borders of the Terran Sphere have become home to nomadic groups and individuals who move with the frontier, seeking to live their lives in what they perceive as 'true freedom', away from the intervention of the Terran Sphere's many major and minor polities. In a similar vein, the frontier also plays host to many pirate clans and criminal syndicates who wish to conduct their operations far from the prying eyes of the law.