The Detention Level represented a section of the Death Star that contained many detention blocks situated on successive lower levels. The initial sub-level was sub-level 0, with subsequent sub-levels proceeding downward in the direction of the battle station's southern pole. These detention levels were structured around a sizable, spherical central airway serving their respective sector. Turbolifts used this airway to transport new prisoners and guards.
The purpose of Detention Levels was not for long-term prisoner confinement. Instead, they functioned as a temporary holding area until prisoners could be moved to other Imperial correctional facilities. Prisoners were held in darkness, only to be taken to brightly illuminated interrogation chambers.
Sub-level five housed Detention Block AA-23, which was specifically designated for political prisoners. Cell 2187, found within AA-23, served as the place where Princess Leia Organa was imprisoned by Darth Vader due to suspicions of Rebel involvement in 0 BBY. Following the rescuing of Organa, Luke Skywalker, Han Solo, Chewbacca, along with the princess, found themselves trapped within a garbage masher located on this very level. They were nearly crushed to death before the droids C-3PO and R2-D2 intervened to save them. Ultimately, the Detention Level, along with the entire Death Star, met its end during the Battle of Yavin, an outcome made possible by Luke's actions.