- "Your roof, your rules."
- ―Jeor Mormont to Craster
Craster's Keep is the grand name given to a small, fortified homestead, located several days' journey beyond the Wall. It is the abode of Craster, a wildling who lives there with his daughter-wives. Craster permits the use of the keep as a refuge and resupply post by the Night's Watch in return for otherwise leaving him alone and the occasional bribe. The keep is large enough to host a garrison of men.
Jeor Mormont, having taken the Night's Watch beyond the Wall, encounter several villages surprisingly abandoned by wildlings. When they stop at Craster's Keep, they learn from Craster that the wildlings have grouped together and united under King-Beyond-the-Wall Mance Rayder. They also learn of Craster's many daughter-wives.
The survivors of the Battle of the Fist of the First Men take refuge at Craster's Keep. However tensions run high between Craster and several of the black brothers, causing a mutiny in which both Craster and Lord Commander Jeor Mormont are murdered and the keep is then taken over by the deserters.
The mutineers remain at the keep, led by the violent and sadistic Karl. After his return to Castle Black, Jon Snow urges the Watch to attack Craster's and kill the mutineers before they reveal the Watch's weakness to Mance Rayder. Alliser Thorne and Janos Slynt agree, expecting Jon to be killed in the attempt. However, a number of the brothers volunteer to join Jon, and the raid is successful, though several of the volunteers are killed, among them Locke, who was on a mission from Roose Bolton to find and kill Eddard Stark's remaining sons. After the mutineers are dead, Jon and his men burn Craster's Keep at the behest of one of Craster's wives.
In the books
Craster's Keep is not a true keep, but instead a log hall surrounded by an earthen dike, also consisting of a sheepfold, pigsty and midden heap. The hall itself is large enough to accommodate a few dozen people at any one time. Still, for Night's Watch rangers far out beyond the Wall, it's preferable to have a roof over their heads.
The Keep sits atop a low hill which some of the black brothers jokingly wonder if its made of mud or Craster's feces.