As with most of the castles in the area an exact date of construction of the castle site at Kinnerton can only be guessed at, however it does get mentioned in a land dispute that led to a royal inquiry in 1252 so it may have been built any time from about 1100. It was probably not built by the Braose family, Lords of Radnor, because it is quite close to New Radnor where their main castle stood so it is more likely to have been constructed by a tenurial knight of whom no record exists. The castle had wet defenses and the pond near the mound is thought to be a surviving part of this A now dry moat surrounds the motte.