The Imperial Fortress served as a military installation and starport for the Imperial forces situated on Yavin 4.
Following the evacuation of Yavin 4 by the Rebel Alliance, the Empire constructed the Imperial Fortress approximately six months after the Battle of Yavin. Vraker Orde held command of the base. A garrison composed of stormtroopers was stationed at this outpost with the purpose of combating remaining Rebel forces hiding within the jungles and preventing any attempts by the Alliance to re-establish Yavin 4 as a base of operations. In an ironic twist, the Rebels briefly seized control of the base not long after its completion.
Later on, personnel from Black Epsilon and Storm Squadron were assigned to the fortress to undertake various space combat missions aimed at suppressing Rebel activity within the Yavin system. Among the officers from these two units were Haymir Rendundi, Field Commander Alozen, and Captain Denner. Lieutenant Colonel Barlow also had his base of operations at the Imperial Fortress.
During 1 ABY, two Imperial technicians, Tellulon and Arlo, were stationed at the outpost. Tellulon was secretly a spy working for the Rebel Alliance, and he eventually succeeded in persuading Arlo to defect and join the Alliance. Around the same period, Wedge Antilles dispatched a team of Rebel operatives to conduct a raid on the Imperial Detainment Facility located within the fortress during the Remembrance Day celebrations. The Rebel agents successfully rescued six Rebel pilots from the facility.