Halo Alpha
Halo Alpha

Largely unexplored, but apparently quite the vacation resort.
— AI Serina[2]

Arcadia was a Unified Earth Government colony located in the Procyon system that was established in 2429[1] and was one of the Outer Colonies.[2]


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[]

Arcadia Colonized

Phoenix-class colony ships colonizing Arcadia.

No need for terraforming, Arcadia was already inhabited by dense jungles and large oceans. It was rich in natural resources, and almost no change was made to its geographical features. Its largest landmasses were divided into six continents; Eire, Pacifica, Mu, Caledonia, Lemuria and Avalon. The human colony was founded in 2429.[1]

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.[3]

The Insurrection[]

The more wild regions of the planet were also home to Insurrectionist bases. At some point prior to 2526 ODSTs were deployed to the planet to drop onto a stronghold.[4] However, the Insurrectionists were still able to keep a large presence on the planet at least until 2531.[5]

Human-Covenant war[]

Main article: Battle of Arcadia

UNSC troops fleeing the Covenant-invaded Pirth City.

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, Shield 0459, from the ruins. Eventually, the Covenant were pushed off by the efforts of the crew of the UNSC Spirit of Fire, allowing much of its civilian populace to be evacuated.

Arcadia's Downfall[]

Main article: Fall of Arcadia

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 supplies. The Covenant would return to Arcadia later in 2549, glassing it.[6]


Arcadia had three Space elevators.[1]



It was seen that the UNSC had a small force on the planet, as there were also Marines already on the planet. Also, ONI had a facility on the planet, analyzing Forerunner artifacts on the planet. There was one known military base on the planet, Fort Deen.

Arcadia also had its own police force, the Arcadian Patrol. It is unknown where they specifically patrolled and where they were headquartered on the planet.

Physical Aspects[]


Halo wars arcadia planet by JJasso-1-

Arcadia as seen from its orbit.

Arcadia was mostly a tropical planet with many, many jungles.[7] There were also beaches on the planet. It was considered a resort world. There were also farms on the planet.


Orbital Locations[]

Known Residents[]

Born On[]

These were the people who were born on Arcadia.


These were the people who lived on Arcadia, but it is unknown if they were born there or came from elsewhere.



Concept Art[]