XI Boötis A system
XI Boötis A was a human-colonized star system, located some 21.8 lightyears from Sol. It was invaded on October 21 2528 by the Covenant. Admiral Cole's fleet responded, defeating the Covenant fleet, but taking heavy casualties in the battle. The colony's fate, whether it was glassed or not by the Covenant, and the state of any colonists survivors, is unknown.
 List of appearances
- Halo Wars: Genesis (First appearance)
- Halo: Evolutions - Essential Tales of the Halo Universe