A prison, also known as a detention block or a jail, was a place where individuals were incarcerated, including specialized buildings or entire planets. Most galactic governments including the Galactic Republic, the Galactic Empire and the New Republic maintained prisons to detain criminals, political dissenters or individuals deemed too dangerous to be allowed into society. Some prisons took the form of factories where the prisoners worked during their sentences; this was known as a work camp, penal work camp or a prison factory.
During the High Republic Era the Galactic Republic operated a number of around the galaxy, including the Republic Correctional Facility on the planet Pipyyr, the Citadel on Lola Sayu which was built in 522 BBY with help from the Jedi Order to contain rogue Jedi and a detention center on the Starlight Beacon. At the same time, the Jedi Order had its own highly secure prison inside the Jedi Temple on the capital planet Coruscant, which they used to contain Sith and other Dark-siders.
With the eruption of the Clone Wars, the combating factions of the Republic and the Confederacy of Independent Systems expanded upon their already existing prison systems to detain newly arrested enemies. The Republic operated a prison specifically for high-status Separatist officers inside the Republic Center for Military Operations as well as the high-security Republic Judiciary Central Detention Center, which was used to detain common criminals. The Jedi Order lost control of the Citadel, which was taken over by the Separatists when they conquered Lola Sayu but at some point during that era they established the Sason Temple which was used to contain a Starweird.
Besides the newly-acquired Citadel, the Confederacy of Independent Systems also operated the space station prisons Starlag XIX and Sunspot, the Unreal City as well as a top-secret detention wing in Dooku's Castle Serenno which he used to keep the Jedi Quinlan Vos.
Following the restructuring of the Republic into the Galactic Empire, the new government inherited many of the Republic's old prisons, including the one on the Center for Military Operations and the Judiciary Detention Center. During the Rebellion era, there were a thousand Imperial prisons in the galaxy including the Spire fortress on the planet Stygeon Prime and the Arrth-Eno Custodial Complex on the capital planet Coruscant. The Death Star had a detention block where Governor Wilhuff Tarkin held Princess Leia Organa until she was rescued by Luke Skywalker, Han Solo, and Chewbacca. The Empire also maintained a secret prison known as the Crypt on the outer reaches of the Anoat system.
The Empire also maintained a vast number of penal work camps, such as the labor camp on the moon Narkina 5, the Delrian Prison Planet, the Oovo Four detention center -which was guarded by Firespray-31-class patrol and attack craft-, the Imperial Detention Center & Labor Camp LEG-817 and the Jubilar.
Following the end of the Galactic Civil War, the victorious Alliance to Restore the Republic restructured itself into the New Republic and took over many Imperial facilities including the Delrian prison and Oovo Four. The New republic also operated other facilities such as the Karthon Chop Fields.
The Canto Bight police headquarters was home to the largest jail on Cantonica.