Cidhna Mine is a prison in Markarth. It is run by the Silver-Blood Family who use prisoners to mine the silver ore inside. It is also home to Madanach, the King in Rags and leader of the Forsworn Rebellion. It is commonly referred to as the most secure prison in Skyrim.
Contrary to popular belief, it is possible to escape Cidhna Mine using a glitch. If the cart found near Duach is pushed into the corner of the wall that leads to the dead end, the Dragonborn can fall through the map and land on the other side of the door they originally entered through. Outrun the guards, or kill them with magic through the side of the door. Once the mine is left, the Markarth Guards will not be hostile.
There is a quest that takes place in Cidhna Mine after the Dragonborn searches for clues about the Forsworn Attacks.
Margret, an undercover operative of the Imperial Legion, was sent to Markarth by General Tullius to retrieve the deed to the mine. The Legion feared the Forsworn and the Silver-Bloods were Stormcloak sympathizers, who wanted to exploit the violent criminals imprisoned in the mine and use them against the Empire.
While investigating the Forsworn Conspiracy at the request of Eltrys, the Dragonborn is either imprisoned here; framed for murdering several notable members of the Silver-Blood family; or infiltrates the mine intentionally, hoping to meet Madanach and disable Forsworn influence over Markarth.
If the Dragonborn returns to Markarth after they have completed the quests that occur at Cidhna Mine and have a bounty, choosing the 'go to jail' option will transport them to Cidhna Mine. To leave the mine, activate one of the ore veins using a Pickaxe, triggering an option to serve jail time.
Finding a shiv, wielding a pickaxe, or using spell to attack any of the inhabitants of the mine provokes everyone nearby to relentlessly strike back at the Dragonborn, with many using magic. Sneaking or Invisibility effects allow picking off the inhabitants more easily as the Dragonborn's lack of armor, accessories, and strong weapons leaves them vulnerable to multiple attacks. Another alternative solution is if the Dragonborn is either a Werewolf or a Vampire Lord, they are able to transform in the mine which is useful for escaping, general combat or killing Madanach if needed.
- Proper Lock Design skill book - In the normally accessible part of the mine.
- Silver Ore Vein (5)
- Three Shivs, unique daggers.
- It is possible to escape the mine after completing the Forsworn Conspiracy mission. Usually, the body of Grisvar the Unlucky still remains, so if the Dragonborn has kept Borgul's Key and Mandanch's Key, they can return through the escape route used in the above mission, plant the keys on the body and get out.
- Also, any equipment desired. Now return to the city, cause havoc, and be thrown into jail. Then escape with the keys and equipment. It is recommended to save though, before doing all this, just in case the body disappears with the equipment.
- It is possible that when returning to the mine, after gaining access through the above quests, the ore veins become unusable. Instead, the ore veins bring up the rest menu as if they are beds.
- It is possible that when returning to the mine, after mining all ore veins during No One Escapes Cidhna Mine, it is impossible for the Dragonborn to serve their sentence, leaving them stuck in the mine. It is possible to escape the mine using Madanach's tunnel by killing Borkul the Beast and grabbing his key.
- There have been instances of the Dragonborn's quest items vanishing after escaping their sentence, along with (what seems to be) every other quest item in the game, such as thieves guild quest targets, the jagged crown, and the elder scroll. The only way to fix this is to load a previous save.
- If the Dragonborn enters the mine and kills ANY of the Silver-Blood mercenaries on guard before the initiation of the quest No One Escapes Cidhna Mine, upon leaving the mine through the main entrance the game will glitch and the screen will go black, without the possibility to load requiring the player to reset the game. The same goes for if the Dragonborn steals the key to the mine from any of the guards and uses it to open anything within the mine.