Well House Oxford Castle

Well House at Oxford Castle is a Grade I listed structure that dates back to around 1071. It served as the motte for Oxford Castle, which was built by Robert d'Oilly to help the Normans control the town and the Upper Thames Valley. The motte has a circular plan, standing approximately 80 feet high, with a base diameter of about 250 feet and a top diameter of about 60 feet. Originally, there would have been a wooden keep constructed by forced Saxon labor.

The Well Chamber, dating from the early 13th century, is made of rubble stone. Its entrance features three stones bearing a shield of arms believed to belong to Fox, Bishop of Winchester, along with the sees of Durham and Newcastle, and Bishop of Exeter. A flight of steps leads down about 20 feet into a hexagonal chamber with a stone vaulted roof supported on chamfered ribs.

Oxford Castle was slighted in 1652. In 1776, New Road was built across the northern part of the Bailey, and in 1785, the County Justices acquired the site to construct a new Oxford Prison, which incorporated the only other surviving elements of the castle: St. George's Tower, St. George's Chapel Crypt, and the batter from the Round Tower. The castle saw little action, except during the Anarchy in 1142 when King Stephen besieged the Empress Matilda and during the Baron's War of 1215. Prison buildings have existed within the bailey since the 12th century.