Barrowton is probably located somewhere in the Barrowlands.
The current ruler of Barrowton is Lady Barbrey Dustin, the widow of the late Lord Dustin who rode with Eddard Stark and fought and died at the tower of Joy.
Lady Barbrey—a Ryswell by birth—joins Roose Bolton, and is one of his chief potential rivals for power in the North after the fall of the Starks. However, her interests lie in her personal vendetta against the Starks rooted in her belief that the Starks took away the man she loved (Brandon Stark, her lover in her youth) and her husband (Lord Dustin). She makes plans to intercept Eddard Starks’ bones and scatter them, so they cannot lie in rest in the crypts of Winterfell.