The scheduled monument includes the remains of a medieval castle mound with baileys to the north and west, and a series of banked and ditched enclosures arranged along its eastern side.
Yielden Castle, on the borders of Northamptonshire, was, at the time of Domesday Survey, the seat of the Barons of Traylly. Their castle is spoken of in an inquisition in 1362, as having then fallen into complete decay. The site is still called the Castlefield, where, from the appearance of the earthworks, the building may be judged to have been a place of great strength. (Castles Of England, Sir James D. Mackenzie, 1896)