Elysium City is an urban center located on the planet Eridanus II.
In 2513, M-EDF 9/21/1, commanded by Lieutenant Colonel Ponder, had an operation in Elysium City. M-EDF 9/21/1 was ordered by FLEETCOM to neutralize the second-in-command to the Insurrectionist leader, Colonel Robert Watts. Against FLEETCOM's insistence on a show of force, Ponder attempted to personally speak to family members of the second-in-command, when a M-EDF 9/21/1 sharpshooter took a hasty shot, completely collapsing the situation.
Elysium City was the city in which John-117 grew up, before he was chosen for the SPARTAN-II Program and replaced with a flash-clone. John originally attended school at Elysium City Primary Education Facility Number 119, where he met both Dr. Halsey and Jacob Keyes in 2517. The school had a substantial playground, including Gravball courts, and a grassy hill where John-117 played King of the Hill.
- Elysium has strong links with the trends of the Halo series, especially through its name. "Elysium" was a Latinization of the Greek word "Elysion," which meant paradise. In Greek mythology, the Elysium Fields were a series of areas where the virtuous dead could exist in happiness.