The motte and bailey castle at Castle Hill survives well as a series of earthwork and buried deposits. These remains will preserve evidence of the form of the fortifications, and the artifically raised ground will preserve evidence of land use prior to the construction of the motte. The association of the motte and bailey castle with the abandoned village of Castle Carlton contributes to an understanding of the inter-relationship of contemporary components of the medieval landscape.
The monument includes the remains of a motte and bailey castle at Castle Hill, Castle Carlton. Castle Carlton lies between South Reston and Great Carlton and was held by Ansgot of Burwell following the Norman Conquest and subsequently by Ralph de la Haye, successor to Ansgot's title. By 1157 Hugh Bardolf had acquired Carlton from Ralph de la Haye. The property was divided amongst the Bardolf family in the 13th century with Castle Carlton passing by marriage to John Meriet in 1275 and remaining in the Meriot family for another century. The motte and bailey castle dates from the 11th or 12th century and is thought to have been built either as a post-Conquest fortification of Ansgot or as a response to the turmoil of King Stephen's reign by Ralph de la Haye, an active supporter of Stephen. The motte and bailey castle was associated with the village of Castle Carlton, 350m to the north east, believed to have been established in the mid-12th century and now abandoned.
The castle takes the form of a motte and double bailey enclosed by ditches, with external banks. The motte, which is located in the north eastern part of a roughly circular ditched enclosure, is a circular mound, measuring 40m in diameter and 8m high. It has steep sides and a flattened top, measuring approximately 15m