The Altier sector existed as a part of the Expansion Region. It encompassed the celestial bodies of Altier, Gerhalt III, and Trebela, in addition to the Ruugia system. The Gerhalt system had already become part of the Galactic Republic as far back as 17,000 BBY. During the Galactic Civil War, Kraxith, the Governor representing the Galactic Empire, dismantled a significant Rebel Alliance cell that was functioning on Trebela.
The sector of Altier was situated within the Slice region of the Expansion Region. By the time of 0 ABY, the Altier sector shared borders with the Hilo and Sepan sectors towards the Rimward direction, the Surron sector in the spinward direction, and the Kailion and Narvath sectors in the trailing direction. In the Coreward direction, the Altier sector also met the Palamut, Tokamac, and Venzeiia sectors, creating a four-way border. The Altier, Gerhalt, Ruugia, and Trebela systems were all located within the Altier sector.
The systems of Gerhalt and Trebela contained the terrestrial astronomical objects Gerhalt III and Trebela, respectively, while the Altier system was home to the celestial body of the same name. The Ruugian noodles originated from the Ruugia system.
The Galactic Republic included the Gerhalt system as early as 17,000 BBY. A hyperlane connected the system to the Surron and Tarmidia systems from that year until 3996 BBY; however, this hyperspace route had disappeared by 3960 BBY.
During the Galactic Civil War, Governor Kraxith of the Galactic Empire governed Trebela. At that time, a major Rebel Alliance network was operating in Trebela's capital city. This network was composed of several Rebel groups functioning independently, with each group unaware of the others' existence or identities. Ultimately, Kraxith succeeded in dismantling this network.
The Altier sector was first mentioned in the StarWars.com Online Companion for the 2009 reference book The Essential Atlas, authored by Daniel Wallace and Jason Fry. In 2012, a map created by Modi illustrating the Altier sector was published in the Online Companion feature "Essential Atlas Extra: Expansion Region."