Azkaban
From Hpwiki
Azkaban is the wizard prison, guarded by Dementors. It is located somewhere in the North Sea. Many wizards and witches prefer to not even discuss it, as the thought of being imprisoned and guarded by Dementors, soulless creatures capable of removing all happy thoughts from a person and forcing them to relive the most unhappy moments of their lives, is terrifying. It is thought to be impenetrable, and until Sirius Black's escape, thought to be impossible to break out. According to accounts provided by Sirius Black, many prisoners eventually stop eating once consumed in their misery, and end up dead from starvation.
There is only one other known wizard prison: Nurmengard. The most notable prisoner being it's creator, Gellert Grindelwald.
Generally, only severe crimes are punished by a sentence in Azkaban. Indeed, the majority of the prisoners during throughout the books are Death Eaters. Known crimes that earn imprisonment in Azkaban are: Any of the three Unforgivable Curses (Avada Kedavra, Cruciatus, Imperius Curses) Impersonating an Inferius (Mundungus Fletcher), being an unregistered animagus (Rita Skeeter was threatened with this punishment by Hermione Granger, forcing entry into restricted sections of the Ministry (Death Eaters in Order of the Phoenix) and plotting against the Ministry (Albus Dumbledore become an outlaw for escaping from Cornelius Fudge and a number of other Ministry officials when Dumbledore's Army was discovered, and he took full responsibility.
Rubeus Hagrid was also imprisoned in Azkaban for being suspected of releasing Slytherin's monster on the school. He was later released when it was discovered he had had nothing to do with it.
Sirius Black is the only wizard known to have escaped Azkaban without outside help. He was able to transform into his animagus form (a big black dog) and slip through the bars. He swam to shore.
Bartemius Crouch Jr. was smuggled out of Azkaban by his father, Bartemius Crouch Sr. and his mother. His mother took Polyjuice Potion to become Bartemius Jr., and he in turn took Polyjuice Potion to take on the appearance of his mother. His mother later died in Azkaban under his identity.
There were two known Mass Breakouts from Azkaban, both of which has outside help from Voldemort and/or the Dementors. In the fifth book, 10 of Voldemort's most loyal followers escaped to return to his service. By the beginning of the seventh book, there has been another mass breakout in which more Death Eaters escaped to resume their service to Voldemort.
It was revealed by J.K. Rowling, that once Kingsley Shacklebolt became Minister for Magic, he removed Azkaban from the control of the Dementors, dispelling a large part of the corruption revolving around the Ministry. It is presumed that some Aurors now have the task of ensuring the prisoners do not escape the prison.

