From A Wiki of Ice and Fire
Sherrer is a stone holdfast in the Riverlands downriver from Mummer's Ford on the Red Fork. The town may be under the dominion of House Vance as Karyl Vance reports on it's status to the Iron Throne. There is an alehouse located next to the stone bridge owned by a man named Joss.
A Game of Thrones
The population of Sherrer is decimated and their houses burned by Lannister men-at-arms posing as brigands at the beginning of the War of the Five Kings. The remaining population is brought to King's Landing as witnesses against those who were raiding. Joss tells of the attack to the Hand of the King, Lord Eddard Stark, and Eddard sends Lord Beric Dondarrion to bring Ser Gregor Clegane to justice.
A Storm of Swords
The Mad Huntsman accuses Sandor Clegane of crimes against the population of Sherrer, stating that girls of six and seven were raped and babies were killed. Sandor replies that he was not at Sherrer, nor the Mummer's Ford.