Roost is a UEG colony situated in the Lambda Aurigae System. Then-Captain Preston Cole took his Gorgon-class heavy destroyer, the UNSC Gorgon, to the system for shore leave. At least part of the planet featured tropical beaches and was known for its fishing.
It was here that Cole met and married Lyrenne Castilla. However, Castilla was revealed to be an Insurrectionist and the captain of the Bellicose, and fled the colony before she could be taken into custody.