Located at the outer edge of the Middle Rim, the sector was surrounded by the Dufilvian, Herdessa and Daimar sectors on the Middle Rim side and the Grohl, Arkanis and Savareen sectors on the Outer Rim side.
The sector is named for the Trans-Nebular Zone, which was the primary "landmark". It contained over a dozen systems, including the Goroth system and the Vestor Nebula, for which the Zone was named. At the center of the Nebula was the Vestor Pulsar, a relatively stable Neutron star. The pulsar served as navigation beacon, but the nebula itself was a hyperspace "dead zone".
The sector contained approximately eighty stars and was located around 10 parsecs within the boundaries of the Mid Rim. Planets in the sector included Milarian, the Baylin Cluster and Goroth Prime. Hyperspace routes towards the systems inside the nebula were dangerous and difficult and often required two or three jumps.
The dangerous nature of the Trans-Nebular Zone made any scouting of the area a difficult operation. Over the time, several dozen scouting and survey ships had been lost due to interferences of the pulsar. Planets and civilizations inside the Zone were discovered relatively late in galactic history.
Around 4000 BBY, the sector was colonized by Corellians as well as exiled Aqualish pilgrims known as Barralenal. Both groups were very expansionistic and soon came into conflict. The sector was ruled at that time by Old Republic Governor Matri Bey. While a capable bureaucrat, she was unable to stop both fractions from going to war. The conflict forced several unaligned planets to take sides, except for Goroth, which managed to remain neutral.
During Imperial rule, the sector was governed first by a Moff who turned warlord, and after his execution, by Moff Nebin Cray. Cray was later replaced by Moff Gal Brello. Between 2 BBY and 4 ABY, Rebel activity was reported in the sector. After the Battle of Endor, the Trans-Nebular sector was probably among the first to overthrow Imperial rule.
- Goroth: Slave of the Empire (First appearance)
- Rebellion Era Campaign Guide
- The Essential Guide to Warfare ("Northern campaign sectors")