Castle Black is the main stronghold of the Night's Watch and the seat of their Lord Commander. The castle is situated along the Wall between Queensgate to the west and Oakenshield to the east, near the center of the Wall, at the northern end of the kingsroad. The village of Mole's Town is located half a league to the south along the kingsroad.
- See also: Images of Castle Black
Castle Black is not a true castle, as it has no walls to defend it to the west, east, or south. Only the Wall stands to the north. It consists of several stone towers and timber keeps. Beneath the keeps and towers, there is a series of subterranean passages called wormwalks which connect all of the buildings. They are rarely used during the summer, but in the winter it is the only way to travel to different parts of the castle.
Castle Black has a small sept run by Septon Cellador but no godswood. Men who follow the old gods can travel half a league beyond the Wall into the haunted forest, where a small grove contains a rough circle of nine weirwood heart trees.
- The Lord Commander's Tower, also called "Lord Commander's Keep", is where the Lord Commander's quarters are located.
- The King's Tower is a 100 foot tall round tower with merlons atop it, overlooking the gate and the foot of the wooden stair leading up the Wall. The entry door is made of oak studded with iron. Although it is reserved for honored guests and named for kings, no king has visited the tower in over a hundred years.
- Hardin's Tower has a broken battlement, from which stone has spilled into the yard below. It has a severe lean.
- The Lance is the tallest tower at the castle, though only a third of the height of the Wall. It is slim and crumbling.
- The Tower of Guards is the strongest of the towers. It lies next to the kingsroad and the Wall, and guards the wooden stair.
- The Silent Tower is a tower at Castle Black.
- The common hall is a great timbered keep where the brothers take their meals. Crows nest in the rafters.
- The rookery is the nesting place of Castle Black's ravens. Consequently, the maester's quarters are located in a stout wooden keep beneath it.
- The armory is where the equipment for weapons practice is kept. Donal Noye forges weapons and armor here.
- The old Flint Barracks is where most of the brothers reside.
- The vaults, located underground, contain food stores and the library. The library contains records and old books that even the Citadel does not have. Amongst other topics, it covers drawings of the faces in the weirwoods, the language of the children of the forest, and scrolls from Valyria.
- The Shieldhall is a feast hall of dark stone. In years past, when the Night's Watch was much larger in number, its walls had been hung with rows of brightly colored wooden shields. When a knight took the black, his shield would adorn its wall and he would take up the plain black shield of the brotherhood.
- The Grey Keep is another building at Castle Black.
There are a series of tunnels underneath Castle Black called wormwalks or wormways, which connect the various keeps and towers. These tunnels are mostly used during the winter, when the cold and snow, sometimes forty or fifty feet deep, make it impossible to travel above ground. The large library of Castle Black lies along one of these tunnels.
- The gate guards the tunnel through the Wall, which is long, twisting and narrow. Three iron gates block the inner passage. Each of these gates is locked and has a murder hole above it. The outer door to the tunnel is solid oak, about nine inches thick.
- The great switchback stair climbs its way up from Castle Black to the top of the Wall. It is made of wooden stairs, anchored by huge beams frozen into the Wall itself.
- An iron cage attached to a winch is used to ascend and descend the face of the Wall. The cage can hold ten men and is located near Castle Black's well. Supplies and barrels of gravel can be transported to the top via the cage.
- Facilities on top of the Wall include a small warming shed for the men on watch located next to the crane.
Castle Black is an ancient stronghold, although the Nightfort, the first castle of the Night's Watch, is said to be twice as old. Castle Black at some point became the seat of the Lord Commander, taking over that role from the Nightfort  at least 600 years ago. Castle Black once held over five thousand fighting men along with their servants, but it now holds about six hundred brothers, said to be one tenth of the five thousand fighting men and there servants, thus putting the number of servants it ones held at approximately one thousand.
A Game of Thrones
Jon Snow and Samwell Tarly are trained by Ser Alliser Thorne as recruits of the Night's Watch at Castle Black. Tyrion Lannister sleeps in the King's Tower during his visit to the Wall, while Jon sleeps in Hardin's Tower. Jon and Sam swear their vows at the nearby godswood north of the Wall and are sworn in as new brothers of the Watch. The bodies of Jafer Flowers and Othor, rangers killed beyond the Wall, reanimate as wights at Castle Black. The Lord Commander's Tower burns during Jon's fight with undead Othor when it tries to kill Lord Commander Jeor Mormont.
A Clash of Kings
Two hundred men from Castle Black accompany Lord Commander Mormont during the great ranging north of the Wall. Maester Aemon remains at the castle because of his age. Samwell Tarly reads a report in the library about Redwyn, a brother who led a ranging to the Frozen Shore during the reign of Dorren Stark, King in the North.
A Storm of Swords
Jon returns to Castle Black after being wounded by wildlings at Queenscrown south of the Wall. Jon and Donal Noye fortify Castle Black as best they can in anticipation of Styr, Magnar of Thenn. Styr's wilding raiders are defeated in a fire trap at the wooden stairs of the castle.
Mance Rayder attacks the Wall with multiple waves of wildings during the battle beneath the Wall. Jon leads the defenders atop the Wall while Donal protects the tunnel through the Wall. After the death of Donal, Aemon tells Jon that he must lead Castle Black until its garrison returns. Jon is sent as an envoy to meet with Mance north of the Wall. As they converse, the knights of King Stannis Baratheon appear and rout the wilding host.
In the aftermath of the battle, Sam finds the common hall burned to the ground and the wooden stair a mound of broken ice and scorched timbers. Stannis occupies the King's Tower, while the Lance, Hardin's Tower, the Grey Keep, the Shieldhall, and other buildings are also crowded with men. Jon is selected as the new Lord Commander to replace Jeor Mormont, who was killed at Craster's Keep.
A Feast for Crows
Samwell searches in Castle Black's library for information about the Others. Sam learns from Lord Commander Snow that he must escort Maester Aemon to Oldtown and then train at the Citadel to become Castle Black's new maester. Because Stannis Baratheon has claimed the King's Tower, and the Lord Commander's Tower has been gutted by fire, Jon establishes himself in Donal Noye's modest quarters behind the armory. 
A Dance with Dragons
Castle Black hosts the army of King Stannis. Jon Snow executes Janos Slynt for disobedience, while Melisandre burns "Mance Rayder". Jon allows thousands of captive wildlings to cross through the Wall to Castle Black, much to the consternation of some members of the Night's Watch. The officers worry there will not be enough rations for the additional mouths. Stannis departs to recruit the northern mountain clans, although Melisandre remains at Castle Black. Some wildlings are recruited by Jon to help the Night's Watch defend the Wall.
Queen Selyse and her queen's men stop at Castle Black on their way to the Nightfort. Alys Karstark arrives seeking refuge and is married to Sigorn of Thenn by Melisandre. Jon has Alys's relative Cregan Karstark imprisoned in an ice cell. Val brings Tormund Giantsbane and his four thousand wildlings to Castle Black, but Bowen Marsh and the mountain clans disapprove of the wildlings settling south of the Wall.
Lord Commander Snow agrees to disperse the wildings amongst the previously abandoned castles along the Wall. Jon receives a belligerent letter from Ramsay Bolton and, choosing to break his vow to the Night's Watch to remain neutral, decides to go to Winterfell to confront Ramsay. As he prepares, the giant Wun Wun kills one of the queen's men, Ser Patrek of King's Mountain. While Jon is trying to make sense of the situation, he is attacked by Bowen and other members of the Night's Watch.
Chapters that take place at Castle Black
- A Game of Thrones: 19. Jon III
- A Game of Thrones: 21. Tyrion III
- A Game of Thrones: 26. Jon IV
- A Game of Thrones: 41. Jon V
- A Game of Thrones: 48. Jon VI
- A Game of Thrones: 52. Jon VII
- A Game of Thrones: 60. Jon VIII
- A Game of Thrones: 70. Jon IX
- A Clash of Kings: 6. Jon I
- A Storm of Swords: 48. Jon VI
- A Storm of Swords: 55. Jon VII
- A Storm of Swords: 64. Jon VIII
- A Storm of Swords: 69. Jon IX
- A Storm of Swords: 73. Jon X
- A Storm of Swords: 75. Samwell IV
- A Storm of Swords: 76. Jon XI
- A Storm of Swords: 78. Samwell V
- A Storm of Swords: 79. Jon XII
- A Feast for Crows: 5. Samwell I
- A Dance with Dragons: 3. Jon I
- A Dance with Dragons: 7. Jon II
- A Dance with Dragons: 10. Jon III
- A Dance with Dragons: 17. Jon IV
- A Dance with Dragons: 21. Jon V
- A Dance with Dragons: 28. Jon VI
- A Dance with Dragons: 31. Melisandre I
- A Dance with Dragons: 35. Jon VII
- A Dance with Dragons: 39. Jon VIII
- A Dance with Dragons: 44. Jon IX
- A Dance with Dragons: 49. Jon X
- A Dance with Dragons: 53. Jon XI
- A Dance with Dragons: 58. Jon XII
- A Dance with Dragons: 69. Jon XIII
- A Game of Thrones, Chapter 19, Jon III.
- A Storm of Swords, Map of Beyond the Wall
- A Game of Thrones, Chapter 21, Tyrion III.
- A Clash of Kings, Chapter 6, Jon I.
- A Game of Thrones, Chapter 48, Jon VI.
- A Game of Thrones, Chapter 41, Jon V.
- A Storm of Swords, Chapter 55, Jon VII.
- A Storm of Swords, Chapter 48, Jon VI.
- A Feast for Crows, Chapter 5, Samwell I.
- A Dance with Dragons, Chapter 69, Jon XIII.
- A Storm of Swords, Chapter 75, Samwell IV.
- A Storm of Swords, Chapter 64, Jon VIII.
- A Game of Thrones, Chapter 26, Jon IV.
- A Storm of Swords, Chapter 69, Jon IX.
- A Storm of Swords, Chapter 56, Bran IV.
- George R. R. Martin's A World of Ice and Fire, Castle Black.
- A Game of Thrones, Chapter 52, Jon VII.
- A Storm of Swords, Chapter 73, Jon X.
- A Storm of Swords, Chapter 79, Jon XII.
- A Dance with Dragons, Chapter 10, Jon III.
- A Dance with Dragons, Chapter 17, Jon IV.
- A Dance with Dragons, Chapter 21, Jon V.
- A Dance with Dragons, Chapter 44, Jon IX.
- A Dance with Dragons, Chapter 49, Jon X.
- A Dance with Dragons, Chapter 53, Jon XI.
- A Dance with Dragons, Chapter 58, Jon XII.