Arcadia

Arcadia was a United Nations Space Command colony located in the Procyon System, and one of the Outer Colonies.

The Forerunners
The Forerunners apparently had a presence on Arcadia before the Forerunner-Flood War, leaving behind a building complex that later became a site of conflict in 2531.

Human Colonization
Upon Human discovery of Arcadia, the planet had no need for terraforming, already inhabited by dense jungles and large oceans. Arcadia was rich in natural resources, and almost no change was made to its geographical features. The UNSC established the largest landmasses into six continents; Eire, Pacifica, Mu, Caledonia, Lemuria and Avalon. Pirth City in Mu, became the largest city on the planet, and soon the capital city.

Arcadia became a center for agriculture, research and recreational activities. It was also home to the Deep Space Research Array. However, despite all of this, Arcadia's population and structures were all very clustered, leaving huge areas of the planet unexplored.

Human-Covenant War
By 2531, it had a population of approximately three million. However, it became a site of conflict in 2531, caught up in the Human-Covenant War, after a Forerunner stellar map on Harvest pointed the Arbiter Ripa 'Moramee towards the colony. Over the course of the battle, the Covenant managed to extract the location of a Shield World from the ruins. Eventually, the Covenant were pushed off by the efforts of the crew of the, allowing much of its civilian populace to be evacuated. The capital city of Pirth would soon become overtaken by nature. Meanwhile, the remaining colonists formed the farming community of Abaskun on the continent of Mu. It would remain a mostly lawless region, but continued to supply the UNSC with food. The Covenant would return to Arcadia later in the war, destroying it.

Main Continents

 * Eire
 * Pacifica
 * Mu
 * Abaskun, a settlement on Mu.
 * Pirth City - The capital city of Arcadia.
 * Caledonia
 * Lemuria
 * Avalon

Other Locations

 * Deep Space Research Array - A research facility on Arcadia.
 * ONI Base - An ONI facility in Arcadia's jungles.
 * Forerunner ruins - A complex of Forerunner ruins near the ONI base.

Trivia

 * It may have been named after the actual Arcadia, a region and city south of Greece in the Peloponnesus.
 * Arcadia is also a name for a paradise in Greek mythology, as well as in later fiction.
 * The Arcadian Patrol was the main law enforcement force on the planet.
 * The original idea for Arcadia was pitched to Joseph Staten by Graeme Devine. Staten liked the idea so much, that he mentioned it in his novel Halo: Contact Harvest. This was explained by Devine in a Halo Wars video.
 * Arcadia is the setting for the RISK version of the Halo Wars board game.
 * Arcadia is also the homeworld of professor Ellen Anders, although she does not at all reflect on this when the colony is attacked.
 * In the Halo Encyclopedia, Arcadia is falsely referred to as an Inner Colony on page 286.