Human colonies

The term human colonies refers to the vast number of colony worlds surveyed and/or colonized by humans within the Unified Earth Government. The planets under the jurisdiction of the UEG, together with humanity's homeworld, are collectively referred to as "Earth and Her Colonies". While the concept of space colonization originated in the 20th century, its practice did not become successful until the 22nd century. As of 2490, a total of 800 colonies were under the influence of the UEG.

Concept
The concept of space colonization was born out of the need to expand human habitation outside of Earth to prevent overpopulation, to alleviate the consumption of Earth's resources by conducting planetary mining on other worlds, and to better understand the universe as human civilization expanded. Various approaches were suggested to achieve this, such as colonization efforts of the Moon and Mars, building facilities on orbiting asteroids and creating artificial platforms.

Prehistory
Over 110,000 years ago, humanity was an advanced, spacefaring race, and had colonized thousands of worlds across the Orion Arm of the galaxy. However, after being exhausted by the parasitic Flood and eventually suffering a disastrous defeat against the Forerunners in the Human-Forerunner War, the Forerunners forcibly regressed humanity to a Tier 7 species and all traces of this advanced civilization were erased.

Interplanetary age
The first recorded success of human colonization in the modern age was made in the later half of the 21st century, more specifically in 2080. The Moon and Mars saw humanity's first expansion, followed by a number of asteroids and the natural satellites orbiting Jupiter. The rapid pace of interplanetary colonization was driven by commercial interests more than the efforts on the part of national governments: Earth bio- and nanotechnology corporations sought to conduct scientific research unhindered by Earth's international law as well as its gravity. Mars, in particular, quickly became an important hub of leading-edge science and industry, and would continue to be so for hundreds of years, particularly in the area of spaceship manufacturing. Advancements in terraforming technologies transformed many of the formerly inhospitable planets and moons of the Solar System into worlds capable of sustaining life.

Despite these successes, the efforts did not solve Earth's overpopulation issue. It eventually led to political unrest, contributing to the formation of political movements promising independence from the national governments on Earth and the perceived oppression by the United Nations. Operating across the colonized worlds and orbital platforms of the Sol system, the Frieden movement and the Koslovics were the most prominent of these rebel factions. Beginning with a Frieden attack on the United Nations colonial advisers in the Jovian Moons and the subsequent UN response, battles were fought over the colony worlds—as well as Earth itself—from 2160 to 2170, culminating in a UN victory in the Interplanetary War. The outcome of the space wars led to the establishment of the Unified Earth Government as a centralized governing body tasked to ensure Earth's influence over the colony worlds and a powerful, united military force known as the United Nations Space Command.

Expansion beyond Sol system
The technological innovation of the Shaw-Fujikawa Translight Engine in 2291 sprung the human civilization into the space-faring age, allowing them to travel beyond Sol system. Half a century later, the UEG constructed its first line of colony ships - led by Odyssey - to initiate the expansion of human habitation, relieving the growing pressure of overpopulation on Earth and the off-world colonies across the Sol system.

Inner Colonies and Outer Colonies


As faster-than-light travel was still new and highly expensive, potential colonists were subjected to rigorous physical and mental testing to determine their suitability for the extrasolar colonization programs. As such, the colonists who formed the basis for the 210 first-wave colonies settled before 2390 formed humanity's elite; these worlds would later be known as the Inner Colonies. Earth and the Inner Colonies soon became the political and economic basis of the UNSC as humanity began expanding to the Outer Colonies. By the time the settlement of the Outer Colonies began, many of the initial difficulties of interstellar travel had been alleviated; by extension, the selection criteria for the colonists became far more lax, resulting in the populace of the Outer Colonies being far more varied than that of the prestigious Inner Colonies.

Colonial expansion continued and by 2490, UNSC colonial space encompassed over 800 worlds in the Orion Arm. The success of colonization of the Outer Colonies made the Inner Colonies the primary stronghold, both military and economic, though they relied heavily on raw materials supplied by the Outer Colonies. During this period, the planet Reach (orbiting Epsilon Eridani, right on Earth's metaphorical doorstep) became the UNSC's primary naval yard and training academy. Reach was a major producer of warships and colony vessels, as well as a training ground for covert operatives and Special Forces. The Inner Colonies' reliance on the Outer Colonies prompted the Unified Earth Government to maintain its hold over the Outer Colonies, but inevitably began to lose its ability to do so as the Outer Colonies eventually surrounded the core worlds and far surpassed them in number. The overbearing influence of the Earth government, enforced by the UNSC and the Colonial Military Administration, led to a growing secessionist sentiment among Outer Colony citizens. The more radical elements of this movement took up arms against the UNSC, sparking the Insurrection in the late 2490's.

At its peak, the UNSC encompassed a number of star systems, with hundreds of planets, moons and planetoids settled by colonists, some terraformed to greater degrees than others depending on the local conditions and presence of indigenous life. The Inner Colonies encompassed a region of space in at least a 10.5 light-year three-dimensional radius from Earth. Beyond that were the Outer Colonies. Other colonies were established even further - Coral, at 42 light-years; and Madrigal, which lay in the 23 Librae system, 83.7 light-years from Earth. In 2456, Harvest was the furthest Outer Colony, at six weeks of Slipspace travel away from Madrigal and two months from Reach.

The Covenant War
On April 20, 2525, contact with the Outer Colony, Harvest, was lost. After failing to re-establish contact with Harvest, the Colonial Military Administration sent a scout ship, the Argo, to investigate. Contact with the Argo was subsequently lost after the ship arrived in the Harvest system, plunging humanity into a deadly war with an alien hegemony known as the Covenant. Harvest was glassed from orbit, and marked the beginning of a 28-year war with the Covenant. During the war, hundreds of human colonies were destroyed and billions of human civilians and military personnel were killed by the Covenant. Following the conclusion of the war, an extensive reconstruction process began in order to rebuild humanity's shattered colonial empire. By 2589, glassed colonies like Reach had been re-terraformed to some degree and open for re-settlement.

Inner Colonies

 * Epsilon Eridani system
 * Reach - Glassed in 2552, reterraformed by 2589
 * Circumstance - Unknown status, likely glassed
 * Tribute - Attacked in 2552, reclaimed and resettled by 2558
 * Beta Gabriel - Unknown status, likely glassed
 * Tantalus - Unknown status, likely glassed
 * Sol system
 * Earth - Under UEG control
 * Mars - Unknown status, likely under UEG control
 * Jovian Moons - Unknown status
 * Pluto - Under UEG control
 * Ectanus 45 system
 * Chi Rho - Unknown status
 * Actium - Glassed in May 2545
 * New Carthage - Under UEG control
 * Skopje - Glassed in 2547

Outer Colonies

 * 23 Librae system
 * Madrigal - Glassed in 2528
 * 26 Draconis system
 * Levosia - Unknown status
 * Charybdis system
 * Charybdis IX - Glassed
 * Chi Ceti system
 * Chi Ceti 4 - Attacked by Covenant in 2525; still held
 * Eridanus system
 * Eridanus II - Glassed in 2530, resettled by 2557
 * Epsilon Indi system
 * Harvest - Glassed in 2525, recaptured by UNSC in 2531
 * Groombridge 1830 system
 * Groombridge-1830 - Unsuccessfully attacked by Covenant
 * Groombridge 34 system
 * Station Delphi - Unknown status
 * Procyon system
 * Arcadia - Glassed in 2549
 * Green Hills - Glassed in 2525
 * Second Base - Glassed in 2525
 * Hat Yai - Glassed in 2528 or 2529
 * Talitsa - Insurrectionist-controlled as of 2558

Other/unspecified

 * 111 Tauri system
 * Victoria - Unknown status
 * Beta Hydri system
 * Beta Hydri VI - Unknown status
 * Brunel system
 * New Llanelli - Glassed in 2546
 * Circinius system
 * Circinius IV - Glassed in 2526
 * Cygnus system
 * Cygnus - Unknown status
 * New Jerusalem - Glassed in 2552
 * Draetheus system
 * Draetheus V - Destroyed in 2553 - 2557
 * Ectanus 45 system
 * Chi Rho - Unknown status
 * Erebus system
 * Erebus VII- Unknown status
 * Hellespont system
 * Troy - Glassed in 2537
 * Harmony - Glassed in 2537
 * Hydra system - Unknown status
 * Lambda Aurigae system
 * Roost - Unknown status
 * Lambda Serpentis system
 * Jericho VII - Glassed in 2535
 * Leonis Minoris system - Three colonies, two glassed in 2537
 * Luyten 726-8 system
 * Luyten
 * Paris system
 * Paris IV - Glassed
 * Sigma Octanus system
 * Sigma Octanus IV - Unsuccessfully attacked by Covenant in 2552.
 * Zeta Doradus system
 * Onyx - Disintegrated, slipspace-based core still intact


 * Algolis - Attacked, unknown status
 * Andesia - Unknown status
 * Ariel - Unknown status
 * Asmara - Attacked, most likely glassed
 * Asphodel - Unknown status
 * Atlas Moons - Still held
 * Ballast - Unsuccessfully attacked by Covenant
 * Biko - Glassed in 2525
 * Bliss - Glassed in 2526
 * Boundary - Unknown status
 * Cascade - Still held
 * Concord - Still held
 * Coral - Attacked in 2552, most likely glassed
 * Cote d'Azure - Glassed
 * Criterion - Attacked, unknown status
 * Crystal - Unknown status
 * Cyrus VII - Unknown status
 * Draco III - Glassed
 * Dwarka - Glassed
 * Emerald Cove - Abandoned in 2542
 * Eirene - Glassed
 * Endymion - Glassed
 * Far Isle - Unknown status
 * Forseti - Still held
 * Fumirole - Attacked, unknown status
 * Gilgamesh - Unknown status
 * Hellas - Unknown status
 * Herschel - Unknown status
 * Imber - Attacked, unknown status
 * Juneou - Unknown status
 * Kholo - Glassed
 * Lenapi - Still held
 * Lodestone - Unknown status
 * Lostwithiel - Glassed
 * Mamore - Still held
 * Meridian - Glassed
 * Minister - Still held
 * Miridem - Attacked, most likely glassed
 * New Constantinople - Unknown status
 * New Harmony - Unsuccessfully attacked by Covenant
 * Oasis VI - Unknown status
 * Oban - Still held
 * Paradise Falls - Unknown status
 * Partition - Still held
 * Reynes - Glassed
 * Ruthersburg - Unknown status
 * Sansar - Glassed
 * Sargasso - Attacked, unknown status
 * Terceira - Still held
 * Terra Nova - Unknown status
 * Venezia - Insurrectionist-controlled as of 2553
 * Verent - Unknown status
 * Verge - Attacked, stripmined by Covenant for helium-3