The Resistance established a headquarters on Ajan Kloss, a jungle moon, following the First Order's destruction of their previous base located on D'Qar. This new location was composed of two distinct areas: a modest landing area designated for the starfighters of the Resistance and a naturally formed cavern that functioned as a hangar for the Tantive IV. Both of these sections were situated within the geographical region known as the Klosslands. Subsequently, after the events of the battle of Exegol, the Citizens' Fleet made their way back to this base.
The Resistance's starfighters utilized this specific area of the base as a landing zone. To prevent detection by the First Order during potential scans of Ajan Kloss, the Resistance deployed sensor scattering nets above the trees. These protective nets allowed the Resistance to safely land and conduct repairs on their inventory of aircraft. The Resistance was able to land and repair their nine RZ-2 A-wings, six B-wing Mark IIIs, seven T-70 X-wings, seven BTA-NR2 Y-wings, and the troop transport Fortitude onto the surface of Ajan Kloss.
A natural cave, formed from limestone and situated near the starfighter landing zone, served as both a hangar for the Tantive IV and the central command post for the Resistance. Due to the base's incomplete construction phase, the Tantive IV, which was General Leia Organa's flagship, also functioned as a power generator, living quarters, and a primary meeting place. Rey Skywalker maintained a designated area within the cave, where she dedicated her time to studying ancient Jedi texts obtained from the temple on Ahch-To, repairing her lightsaber, and examining the kyber crystal contained within it. The command center was positioned on the cave's left side, with the Tantive IV occupying the central area, and Rey's Jedi study located on the far right. Additionally, a small room was designated as Organa's private sleeping quarters, while other personnel not on duty slept aboard the Tantive IV. The Resistance also constructed a laser-cut trail, which led from the cave to the starfighter landing zone.
Before the Galactic Civil War commenced, the jungle moon of Ajan Kloss was mapped but kept hidden from the Imperial Senate. Ajan Kloss, along with Yavin 4 and Dantooine were concealed from the Galactic Empire because it was a potential rebel base. Following the Battle of Endor, Ajan Kloss did serve as a small outpost for the Rebel Alliance. Furthermore, it served as a training location for Luke Skywalker and Leia Organa. After the First Order's destruction of the Resistance base on D'Qar, which forced the remaining Resistance forces to evacuate their Crait outpost, General Organa decided to establish a base on Ajan Kloss, as a tribute to her past Jedi training.
Around 35 ABY, the Resistance base was still under construction, and so the Tantive IV provided the power necessary to operate the base.