The 8th Sector Army existed as one of twenty Sector Armies within the Grand Army of the Republic throughout the duration of the Clone Wars. This Sector Army was comprised of 147,456 clone troopers, organized into four corps, and was operationally linked to one of the Republic Navy's twenty designated fleets. During the conflict, this army established its headquarters on the planet Ord Mantell, which is situated in the Mid Rim region of the northern part of the galaxy.
During the Clone Wars, the 8th Sector Army, as a component of the Grand Army of the Republic, was tasked with safeguarding its designated operational area. Initially, at the war's onset, the Grand Army was structured into ten Systems Armies. These were further subdivided into two Sector Armies, each responsible for a specific sector of the galaxy. Therefore, the 8th Sector Army was paired with another Sector Army within the same Systems Army. Alongside the 7th through 12th Sector Armies, the 8th Sector Army operated in the northern region of the galaxy.
Similar to other Sector Armies, the 8th Sector Army had a Galactic Republic Haven-class medical stations assigned to it for medical support. It also included a complement of 147,456 clone troopers distributed across four corps. Like its counterparts, the army was affiliated with one of the twenty numbered fleets belonging to the Republic Navy.
Following the First Battle of Geonosis during the years of the Clone Wars, the shadowport planet of Ord Mantell, located in the Mid Rim, became a hub for various Republic Military facilities. These included a storage facility, barracks, and a fleet support base. Consequently, Ord Mantell served as the central command location for the 8th Sector Army throughout the conflict.
Within the current Star Wars canon, the 8th Sector Army was first allued to as one of the twenty Sector Armies inside the eighteenth issue of the De Agostini publication, Star Wars: Build the Millennium Falcon, which was released around May 6, 2015. Its specific identification occurred later in the forty-eighth issue, which was made available around December 2 of the same year. In the Star Wars Legends timeline, the Eighth Army was introduced in the 2012 reference guide The Essential Guide to Warfare, authored by Jason Fry and Paul R. Urquhart.
- Star Wars: Build the Millennium Falcon 18 (Guide to the Galaxy: Sectors of the Galaxy) (First mentioned) (Indirect mention only)
- Star Wars: Build the Millennium Falcon 48 (Guide to the Galaxy: Visiting Ord Mantell) (First identified as 8th Sector Army)
- " Kashyyyk and Other Planets in the Mid Rim " — Star Wars Encyclopedia