Horizon Base functioned as an Imperial installation, serving as both a shipping port and a [fuel](/article/fuel]ing station. It was positioned on a planet within the Outer Rim Territories of the galaxy. By 3 BBY, the Empire controlled the sector where it was located. The base emerged from underground facilities resembling portals. It featured a total of six docking zones, with circular structures surrounded by numerous individual docking bays. Three of these bays directly encircled the main spire, while the other two were situated further away. The main spire of the base also extended slightly higher than the other docking areas. The exterior of the base contained cargo containers, barrels, and a market. Civilians were present at the station, trading items such as droid components. Inside, the station comprised corridors and cargo loading zones.

During the Galactic Civil War in the year 3 BBY, the Spectres, a rebel group including Hera Syndulla, Kanan Jarrus, Sabine Wren, Garazeb Orrelios, and Ezra Bridger, raided Horizon Base to acquire fuel necessary for the fleet of Phoenix Cell. During this operation, the rebel astromech droid Chopper was inadvertently left behind after the others departed with the stolen fuel, as he was guarding the ship. Stranded, the droid boarded the class four container transport designated 241 that was leaving the station. With the assistance of a new ally, the inventory droid AP-5, he was soon reunited with Phoenix Cell.

By 34 ABY, the First Order had control of Horizon Base. During the First Order-Resistance War, Resistance operatives Poe Dameron, Finn, and Gannis Ducain journeyed to Horizon Base on a mission to enlist Mezlo's Oruan group to join the Resistance. Upon infiltrating the base, Finn and Ducain were spotted by two stormtroopers, who they defeated by dropping cargo crates on them before fleeing. While navigating the base's interior, the two agents were captured by a candori and encountered Mezlo's group of refugees. They were interrupted by additional stormtroopers, whom they fought off, and attempted unsuccessfully to recruit the Oruans, as they preferred to seek their place elsewhere. Nevertheless, the Oruans agreed to assist the Resistance when needed.

Horizon Base made its debut in "The Forgotten Droid," the nineteenth episode of the second season of the animated television series Star Wars Rebels. The episode was initially broadcast on March 16, 2016.