Seat of House Karstark, a strong castle upon a forested river in the eastern half of the North, south of the Bay of Seals and west of the Grey Cliffs. It is smaller and meaner than Harrenhal, which is no great insult, for so is every castle in the Seven Kingdoms.
Karl's Hold
Karlon Stark, a younger son of Winterfell, was granted these lands a thousand years ago for putting down a rebel lord, and the hold he raised was called Karl's Hold. The name wore down to Karhold as the centuries passed, and the Karhold Starks wore down to Karstarks in the same fashion. The white sunburst on black is the direwolf's blood turned to another device, and no Karstark has ever forgotten it.
Blood and Betrayal
Lord Rickard Karstark brought three hundred horse and near two thousand foot to Winterfell when Robb Stark called the banners, and lost two sons to Ser Jaime Lannister in the Whispering Wood. His grief cost him his own head when he murdered two Lannister boys held captive at Riverrun. In A Dance with Dragons the castellan Arnolf plots to take the seat from his captive nephew, and Lady Alys flees through the snows to Castle Black.