It was a motte and bailey on Carberry Hill. Excavations in 1902 identified the remains of a small stone chamber surrounded by a ditch.[3] Fragments of pottery and the remains of a sword were also found.[4] A coin from the period of Edward IV was also uncovered.[2]
Around the site of the castle is a 60 metres (200ft) long bank which is around 1.5 metres (4ft 11in) high and a ditch.[5] An area west of the inner bailey has been identified as a possible pillow mound.
The origin of the castle is unclear. It may have been part of the manor of Kewstoke or alternatively Hutton. The two manors were combined and given by Henry I to Geoffrey de Dun. In 1214 Locking was given to Woodspring Priory and would have ceased to have military significance.[6]
