Castle Cerwyn is the seat of House Cerwyn in the north. It is located by the western branch of the White Knife. Because of the closeness of their castles, the Cerwyns often visit the Starks, as they are only half a day's ride from Winterfell.
A Clash of Kings
After the fight at Torrhen's Square, Ser Rodrik Cassel sends a raven from Castle Cerwyn to Riverrun informing Catelyn Stark that her sons, Bran and Rickon, have been killed by Theon Greyjoy. Rodrik marches from Cerwyn to Winterfell to retake Winterfell from Theon's ironborn.
A Storm of Swords
A Dance with Dragons
- The map of "The North" by Michael Gellatly for The World of Ice & Fire places Castle Cerwyn southwest of Winterfell, by the headwaters of the western branch of the White Knife and near the wolfswood. The semi-canon A World of Ice and Fire labels Castle Cerwyn as southeast of Winterfell on the same branch. The Viewer's Guide for the television adaptation Game of Thrones places Castle Cerwyn south of Winterfell on the river.
- The World of Ice & Fire, The North.
- George R. R. Martin's A World of Ice and Fire, Castle Cerwyn pin on the map of Westeros.
- A Clash of Kings, Chapter 30, Arya VII.
- A Clash of Kings, Chapter 16, Bran II.
- A Clash of Kings, Chapter 55, Catelyn VII.
- A Clash of Kings, Chapter 66, Theon VI.
- A Storm of Swords, Appendix.
- A Storm of Swords, Chapter 55, Jon VII.
- A Dance with Dragons, Chapter 32, Reek III.
- A Dance with Dragons, Chapter 51, Theon I.