From Halopedia, the Halo wiki
2491 was a year in the 2490s in the 25th century.
- 48452-556-EPN644, a member of the Assembly, submits himself for vivisection by the humans, with the intent of sparking an interest in the long-dormant Orion Project.
After January 29
- Gladys Wilson volunteered for the ORION program after a year an a half of special forces, where her superior Aaron Lewis only accepted the transfer to get rid of her.
- A report is made on Onyx, the planet being recommended for colonization.
- Elias Carver publishes a set of theories known as the Carver Findings.
- The Assembly decides to have Onyx removed from the list of potential planets for colonization, due to the advanced alien technology present on the planet.
- The M99 Stanchion presumably enters production for service within the UNSC.
- The position of captain of the Spirit of Fire is transferred from Captain Rehkov to Captain Donald.
These are events that are based around this year, and may not fall on this year specifically.
Between October 25 2490 to October 23 2492
- Halo: Reach, Data pad 5
- Halo: The Flood, chapter 1
- Halo Waypoint - Universe, Factions, Spartans (Retrieved on Oct 20, 2020) [local archive] [external archive]
- i love bees - Axon Clips, Chapter 8: Jan: "The Funeral"
- Halo Waypoint - News, Office of Naval Intelligence//Section 3 - Data Drop One (Retrieved on Oct 28, 2011) [local archive] [external archive]
- Halo: Ghosts of Onyx, chapter 13
- Halo: The Essential Visual Guide, page 194 (Tartarus)
- Halo Encyclopedia (2022 edition), page 254
- Halo Encyclopedia (2009 edition) - Chapter Two: Humans - Civil War, page 44
- Halo: Reach, Data pad 6
- Halo Graphic Novel - Page 122
- Halo Wars, campaign level Cleansing
- Halo: Ghosts of Onyx, chapter 2