Ashton Keynes Castle was in the village of Ashton Keynes, near to the town of Cricklade in Wiltshire, England (grid reference SU049943). Known as Hall's Close, the scheduled monument consists of a ringwork and bailey 100m west of Kentend Farm.
Ashton Keynes Castle Wikipedia
The castle was founded in the 12th century by the Keynes family. Only the earthworks now remain.
Renn has suggested that this castle rather than South Cerney Castle is the one that was captured by King Stephen from Miles of Gloucester during the Anarchy.