The region was an experiment in corporate-controlled worlds settled during the Galactic Republic's Great Manifest Period beginning in 20,000 BBY. Unrelenting exploitation by Corellian and Duros/Neimoidian corporate interests of the worlds of the Corellian Run had impoverished countless native species and contributed to environmental despoliation. Galactic colonization was forced to shift farther eastward towards the Perlemian Trade Route.
Looking for untapped resource-rich worlds, the two galactic powerhouses Alsakan and Coruscant sponsored the exploration and settlement of the future Expansion Region. Competing economic interests between Alsakan and Coruscant led to the First Alsakan Conflict in 17,000 BBY which ended the economic boom of the Great Manifest period. Over the following millennia, the competing holdings of both worlds fought seventeen "Alsakan Conflicts" in the Region. The conflicts devastated many Alsakan colonies while slavery boomed due to the entry of Hutt, Trandoshan and Bothan slavers.
Only the Corellian Run escaped the conflict due to the strong presence of Corellian military warships, which precipitated further colonization west of the Run. Gradually, the western portion on the region became a mixture of prosperous agrarian, industrial and trading worlds known collectively as the Trailing Sectors. The widespread prosperity of this region funded Coruscant's colonization of the Mid Rim worlds.
The Brentaal League extended its hyperlanes into the Region in 4020 BBY. The last Alsakan Conflict ended in Coruscant's favor in 3017 BBY and sealed its monopoly over galactic colonization efforts in the ensuing period. For another millennium, the eastern Slice sectors recovered but were devastated by the New Sith Wars and the Candorian plague during the Draggulch Period (2000—1000 BBY). Many colonies were abandoned as the Republic retreated into the Core Worlds.
Following the Ruusan Reformation, the Republic granted a conglomerate of powerful corporations known as the Expansionist Oligarchy control of the Outer Expansion Zone. These corporations exploited and profited heavily from the raw materials, metals and ores of many worlds. While profits were enormous for these corporations, the region was plagued by internal strife and disturbances. Inhabitants were oppressed while the corporations stripped entire stellar systems of all their resources. Because they controlled communications and transportation to, from, and across the region, very few people knew what was going on in the Expansion Region.
With civil unrest spreading from system to system, the Republic eventually took control of the Region due to mounting pressure from its denizens by limiting or evicting corporate interests. Though most of those corporations moved on to the Corporate Sector in 490 BBY, Expansion Region worlds were still producers of raw materials and ores. However, most natural resources were exhausted.
During the Imperial Period, the Galactic Empire attempted to revive the Slice sectors by developing several key regional centers like Gyndine, Bacrana and Cyrillia into depot stations for civilian and military fleets and encouraging colonization of surrounding systems by corporations and laborers. The Corporate Sector Authority also aided in the development of several subsectors and controlled the Enarc Run until the Battle of Endor.
During the Galactic Civil War, the Rebel Alliance established several bases on depopulated systems. Following the withdrawal of Imperial forces to the Outer Rim Territories following the collapse of Operation Shadow Hand, the Alliance's successor state the New Republic tried rebuilding the region but was interrupted by the Yuuzhan Vong War. Though Yuuzhan Vong agents succeeded in stirring conflict between Osarian and Rhommamool along the Corellian Run, much of the region escaped the war.
The Expansion Region was divided into a number of distinct sectors, which included:
Behind the scenes
According to an email from Jason Fry, the Essential Atlas Online Companion's next update would feature a sector map of the Expansion Region. Such an update eventually occurred in late October of 2012.
- Star Wars: The Old Republic
- Star Wars: The Old Republic: Galactic Strongholds
- Star Wars: The Old Republic: Knights of the Eternal Throne
- Darth Plagueis (Mentioned only)
- Darth Plagueis audiobook (Mentioned only)
- Clone Wars Gambit: Stealth (Mentioned only)
- Clone Wars Gambit: Stealth audiobook (Mentioned only)
- Star Wars: The Clone Wars – "Darkness on Umbara"
- Star Wars: The Clone Wars – "The General"
- Star Wars: Clone Wars Adventures – "Battle of Umbara"
- Star Wars: The Clone Wars – "Plan of Dissent"
- Star Wars: The Clone Wars – "Carnage of Krell"
- Star Wars: The Clone Wars – "The Gathering" (In flashback(s))
- Star Wars: The Clone Wars – "An Old Friend" (In flashback(s))
- Imperial Commando: 501st
- Dark Times 11
- "Wind Raiders of Taloraan" – Star Wars Adventure Journal 5 (Mentioned only)
- The Jewel of Yavin (Indirect mention only)
- Ultimate Core Dump (Mentioned only)
- Star Wars: TIE Fighter
- Legacy of the Force: Sacrifice (Mentioned only)