Halo Alpha
Halo Alpha

The Outer Colonies are the human-colonized planets farthest from the Inner colonies such as Earth and Reach. These colonies were largely unexplored and undeveloped.[1]

By 2536, the majority of the Outer Colonies had been glassed by the Covenant.[2]



Main article: Domus Diaspora

The Inner Colonies were finished and settled in 2390. More and more colonies were continued to be settled. By 2490, the Outer Colonies were effectively established.[2] In the 2500s, the term "outer colony" was used to describe any planet or installation at the edge of Unified Earth Government space.[1]

The Insurrection[]

Main article: Insurrection
Eridanus battle

Operation: TREBUCHET

As humanity expanded, the outer colonies began to experience sentiments of autonomy and political independence from the UEG.[3] By the 2400s, the impotence by the UEG to keep the outer colonies felt to many colonists like an interference on a confederation of independent planets.[4] This began to cause a tremendous amount of stress across human controlled space. In 2492, this stress eventually caused many riots on the colony of Far Isle. With the UNSC unable to control it, they used nuclear weapons to put down the riots and declared Code Bandersnatch.[5] This event has been cited as what sparked the Insurrection.[6]

Many different secessionist movements began springing up and the UNSC responded to these threats. The biggest counter insurgency operation by the UNSC was Operation: TREBUCHET.

Human-Covenant war[]

Main article: Human-Covenant war

Harvest post glassing.

The Covenant had found Harvest in 2525. While there was a small skirmish between UNSC forces and the Covenant beforehand, the war didn't begin until a disastrous first contact. This led to a second battle and a protracted five-year campaign.

Outer Colony Massacres[]

Main article: Outer Colony Massacres

However, at that point, the Covenant's genocidal judgement of humanity had spread to many of the other outer colonies like Biko and Green Hills. ONI, however, kept this fact a secret from the rest of the public up until 2526.[7]

By 2530, there were at least 62,154,022 deaths in the Outer Colonies.[8] In 2536, after ten years of war, most of the Outer Colonies had been lost, and the inner colonies were beginning to be attacked.[2] Jericho VII was among the last major ones to fall.

By 2552, though some Outer Colonies still remained in UNSC hands (mostly remote outposts), most were small and rather insignificant worlds.[9] The few significant colonies still under UNSC control lived in constant fear of Covenant invasion. Some of the remaining colonies were bases for outlaws.


By the time the Human-Covenant war ended on March 3, 2553, tensions were already becoming unsteady in the Outer Colonies. On top of this, Covenant remnants were also occupying other parts of the Outer Colonies.[10]

H5G HTT-EP9 Outbreak

The escalated riots in the outer colonies.

In 2558, after the revelation that John-117 had attacked a peace delegation on Biko, and that ONI abducted children from the outer colonies for the SPARTAN-II program, huge parts of the outer colonies had again started to distrust the UEG. Many turned to the New Colonial Alliance instead.[11]

Following Benjamin Giraud's interruption of a joint UEG Senate and ONI meeting, the Waypoint buoys connecting the inner and outer colonies were shut down.[11] When Benjamin was publicly discredited on ECB, tensions died down and the buoys were turned back on.[12]

The Reclamation[]

Main article: The Reclamation

Cortana sent out Guardians out to systems in the Outer Colonies.[13]


Many of the fashions, and likely other elements of their culture, were behind that of the Inner Colonies; having gone out of style some time before.[14]


The Outer Colonies were colonies at the farthest points along slipspace routes and take a long time to reach.[1] Due to the nature of slipspace itself, even systems known to be close to Earth in realspace can be considered outer colonies, such as Harvest in the Epsilon Indi system.[15]

Known Colonies[]

There are at least 590 Outer Colonies.[2] 36 colony worlds, 21 systems, and 2 space station colonies have been mentioned so far.

System Colony Status
23 Librae system Madrigal Glassed in 2528
The Rubble Abandoned and destroyed except for Habitat Exodus
Alpha Aurigae System Unknown Unknown
Charybdis system Charybdis IX Glassed
Circinius system Circinius IV Glassed in 2526
Chi Ceti system Chi Ceti IV Abandoned in 2525, but reoccupied by UNSC in 2558
Cygnus system Cygnus II Unknown
New Jerusalem Glassed in 2552
Elduros system Aleria Fallen out of UEG control
Epsilon Indi system Harvest Glassed in 2525, retaken by UNSC
Eridanus system Eridanus II Glassed in 2530
Eridanus secundus Destroyed in 2552
Mamore Unknown, likely glassed
Escala system Escala III Still held
Groombridge-1830 system Unknown System attacked in 2530, but still held by UNSC
Hestia system Meridian Glassed in 2551. Under control by the Liang Dortmund company.
Lambda Serpentis system Jericho VII Glassed in 2535
Lambda Aurigae system Roost Unknown
Orrichon system Sedra Shifted away from the UEG during and after the war
Procyon system Arcadia Attacked in 2531. Destroyed in 2549
Sverdlovsk system Talitsa Still held
XI Boötis A system Unknown System attacked in 2528, status otherwise unknown.
Unknown Asmara Glassed
Biko Glassed in 2525, in UEG control
Bliss Glassed in 2526, turned into mining world by BXR Mining.
Carrow Lost to Sangheili settlers in 2552, UEG in process of reclaiming planet.
Cleyell Glassed in 2556[16]
Coral Attacked in 2552, most likely glassed
Cote d'Azure Glassed
Desdoron Unknown
Dwarka Unknown, likely glassed
Green Hills Glassed in 2525
Hat Yai Glassed in either 2528 or 2529
Minab Glassed
Paradise Falls Unknown
Ruthersburg Glassed
Sansar Glassed
Second Base Glassed in 2525
Verent Unknown


Glassed in 2532

Concord Attacked in 2551, still held



  1. 1.0 1.1 1.2 Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo - page 91
  2. 2.0 2.1 2.2 2.3 Xbox.com Halo Storyline (Defunct, Copy on HBO Forums)
  3. Halo Encyclopedia, page 45
  4. Halo Encyclopedia, page 43
  5. Halo: Ghosts of Onyx, page 183
  6. Halo Encyclopedia, page 288
  7. Halo 4: Forward Unto Dawn
  8. Halo: Reach - Collectible: Data Pad 14
  9. Halo: First Strike, pages 98-99: And what did the citizens of the Outer Colonies think? Those who hadn't fled to remote outposts and hidden privateer bases weren't in any position to make trouble. The Covenant didn't take prisoners.
  10. Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo - pages 38 & 39
  11. 11.0 11.1 Hunt the Truth - Episode 09: Phantoms (Part 1)/(Part 2)
  12. Hunt the Truth - Episode 13: In The Bag (Part 1)/(Part 2)
  13. Halo 5: Guardians - Level: Guardians
  14. Halo: Contact Harvest - page 115
  15. Halo: Warfleet - An Illustrated Guide to the Spacecraft of Halo - page 10 & 11
  16. Halo: Escalation Issue 17