The Elchin Littoral is the galactic outward-most region of space controlled by the defunct Covenant, located in the hazy fringes of the Perseus Arm of the Milky Way galaxy. It is an isolated, poorly-charted region that is cut off from the rest of the Covenant Sphere by the void of the Ullos Gulf. Although not entirely starless, stars within the Gulf are far more sparse and spread out than in the spiral arms, with only a small string of stellar clusters providing a bridge between the two regions.

Over the Covenant's existence, less than five hundred systems in the Elchin Littoral were surveyed and charted, with occasional expeditions being launched there. The few permanent settlements in the region only had sporadic contact with the rest of the Covenant. Some old records and tales suggest there may even be forgotten colonies further in the Perseus Arm, settled nearly two millennia ago, but little evidence of these "lost colonies" existed. In the aftermath of the Human-Covenant War, rumors circulated that a massive ex-Covenant fleet departed for the Elchin Littoral from the Sol system, as its fleetmaster correctly anticipated the scale of the civil war that would engulf the empire. Upon capturing an inert UNSC colony ship filled with cryofrozen occupants, he departed for the region in an effort to catch up to a settlement fleet that was spearheaded by his brother, with the hope that his men could avoid the coming crisis.

Known colonies

• Qwalen - the most notable Covenant outpost and reliquary-world in the Elchin Littoral, noted for its Forerunner cities and underground catacombs