The castle motte was built up in several stages, originally being lower in height than today, before being built up during the medieval period and scarped by cutting away at the surrounding stone. It was then reinforced in 1700 with the addition of clay, before having large quantities of earth dumped on it in the late 18th century, and then being terraced in the mid-19th century. The motte is separated from the bailey by a ditch, now crossed by a modern bridge. In the 13th century this point was protected by a D-shaped tower, which still survives, located to one side of the gateway. The causeway steps up to the top of the mound were originally a roofed, stone corridor. There are the foundations of the castle well on the west side of the causeway.