|Star System|| Procyon
Arcadia is the fourth planet from the star, Procyon. It is home to a small rebel presence. The colony's capital is Pirth City, and the planet is covered in Forerunner ruins. It was invaded by the Covenant in 2531.
Arcadia plays an important role in Orion, although it never makes an appearance. When the Colonel was sent to Arcadia, the UNSC were inhumanly disposing of the rebels, even MAC blasting their camps. The Colonel decided at that point to join the rebels. Captain Butcher and a few other crew followed him and formed Strike-team Orion on Reach.