From Halopedia, the Halo wiki
Endymion was a human colony. It is the homeworld of Catherine Halsey, who was born in Port Vernon. At some point during the Human-Covenant War it was glassed by the Covenant. Endymion Gifted was an elite educational academy on the planet.
Endymion was a frontier world; although its towns offered comfortable middle-class living, wilderness always loomed beyond the boundaries of its settlements.
List of appearances