From the National Heritage List for England: Details The monument includes the site of a castle of Norman origin and its defended approach causeway, and a Bronze Age burial mound with an encircling ditch. A large defensive earthen bank or rampart encloses the summit of Castle Hill, except on the western side where the steep slope was sufficient defence. The rampart averages some 20m in width and, when taken in conjunction with the deep outer ditch, presented a long and steep slope to any would-be attacker. Within the enclosed area is a smaller oval enclosure surrounded by another ditch. This inner enclosure, or ringwork, measures 105m east-west by 72m north-south and was the site of the main residential buildings of the castle as well as a small chapel. Between the ringwork and the outer bank was the bailey; an enclosed area in which ancillary buildings such as soldiers' accommodation, storage huts, workshops and stables would have been sited. A raised causeway crosses the bailey, joining the entrance to the ringwork on its eastern side with the entrance to the castle to the north east. This is the only original entrance, the other routes into the castle having been created more recently. Part excavation by General Pitt-Rivers in 1878 revealed a number of internal features, including a well over 29m deep within the ringwork. Several of his excavation trenches are still visible as hollows. Leading north eastwards from the castle is a causeway with a 3m wide ditch and bank on its western side. For over 100m the causeway stands raised above the general ground level. Also in this area is a low earthen mound 16m in diameter, slightly truncated by the causeway, which marks the site of a Bronze Age burial. The ditch around the mound is no longer visible Reasons for Designation Ringworks are medieval fortifications built and occupied from the late Anglo-Saxon period to the later 12th century. They comprised a small defended area containing buildings which was surrounded or partly surrounded by a substantial ditch and a bank surmounted by a timber palisade or, rarely, a stone wall. Occasionally a more lightly defended embanked enclosure, the bailey, adjoined the ringwork. Ringworks acted as strongholds for military operations and in some cases as defended aristocratic or manorial settlements. They are rare nationally with only 200 recorded examples and less than 60 with baileys. As such, and as one of a limited number and very restricted range of Anglo-Saxon and Norman fortifications, ringworks are of particular significance to our understanding of the period. The ringwork at Castle Hill is the largest and most complete ringwork in the south east of England and survives to a large extent undisturbed by later activities. Its archaeological potential is therefore considerable, as has been demonstrated during small-scale part excavation by General Pitt-Rivers in 1878. These excavations have also led to above average archaeological documentation of the castle. The causeway linking the castle to the approach lane is a rare survival of an originally common component of castles and one which demonstrates the use of natural defences beyond the limits of the castle itself. The Bronze Age bowl barrow which was incorporated into the causeway adds to the diversity of the monument and is itself of considerable archeological potential since it shows no evidence of having been seriously disturbed.