Ballast

Ballast is a UNSC-controlled colony, possibly in the Inner Colonies. During the Human-Covenant War, the Battle of Ballast is rumored to be a battle in which the UNSC Defense Force defeated the Covenant in the later years of the war. The colony was apparently still intact during the Battle of Earth, as evidenced by active transports from the colony to the Quito Space Tether.

Trivia

 * On the Halo 3 multiplayer map Orbital, one of the incoming transports is from Ballast.