Psi Corps HQ sat over in a corner of Earthdome, near the wall. It was a collection of buildings, the centerpiece of which was a tall, alabaster-white office tower bearing the Psi Corps emblem. Surrounding the tower were a number of smaller buildings that served as training facilities, organizational buildings, and residential apartments.
Level 12 Investigations
Much of the complex was used as apartment space or dormitories for resident telepaths, including academy recruits, commercial telepaths, and members of Level 12 Investigations. It was large enough to feature a concert hall and other care and entertainment facilities specifically for personnel as a way to avoid interacting with the mundane populace. Psi Cop Alfred Bester maintained an apartment on-site for when he was on Earth.
Trouble on Babylon 5
In 2262, a tragedy occurred at HQ when one fresh academy graduate - Jonathan Harris - murdered his roommate in the course of a scan-and-counter exercise. Psi Cop Alfred Bester and two MetaPol recruits - Lauren Ashley and Chen Hikaru - are dispatched to Babylon 5 to retrieve him. During their investigation, HQ forwards facsimile copies of all materials in Harris' file, aiding them in their task.
Some time before 2267, Psi Corps HQ was assaulted by members of the Telepath Resistance, led by Lyta Alexander. The building was destroyed in the attack, and the organization fell apart in the aftermath of the conflict to be replaced by the Psionic Monitoring Commission.