The Seropian was a "center for active retirement" in the Greater Chicago Industrial Zone, within the former United States on Earth. Before her death, it housed Avery Johnson's much loved Aunt Marcille in the 37th floor.
The building was a high-rise featuring at least 37 floors. It seemed to have a lower level where retirees could exercise and talk, and an upper level where retirees would reside.
List of appearances
- Halo: Contact Harvest (First appearance)
- Halo: Contact Harvest, Chapter 2, page 38