The United States Colonial Marine Corps (USCMC) or USCM, commonly known as the Colonial Marines, is the successor to the United States Marine Corps and their “force-in-readiness”, who are at all times ready to operate in environments far from home.

The Colonial Marines, along with the United States Army, are part of the United Americas Allied Command. The primary duties of the Colonial Marines are to maintain security on all United Americas signatories and colonies, and serve as the vanguard of any major combat operation. They have fought on more than two dozen worlds, including Tientsin (8 Eta Bootis A III), Helene 215, Linna 349, BG-386, LV-1201, LV-742, and the infamous Acheron LV-426.