The castle in Hunmanby was built originally by Guilbert de Gant (1048-1095) in the 11th century but then destroyed in the period. It was built in the time of The Anarchy which was during the reign of King Stephen between the years of 1135 to 1154AD. All that remains of the castle are earthworks. In the 14th century, the site of the earlier motte was referred to as ‘Castlegarth’, while a field containing the bailey is called ‘Erlesing’.
The motte occupied the highest point on Castle Hill which provided an easily defended site requiring little modification. The western edge of the motte is defined by a ditch, 10m wide and 3m deep. The ditch once surrounded the motte but has been infilled to the south and east. To the north the motte is bounded by the steep scarp of the road embankment. The motte is estimated to be 60m in diameter and the top is about 4m above the surrounding land surface. Historical and aerial photographic research has identified the original extent of the bailey and, although the southern part has been altered by terracing associated with modern buildings, the northern area remains undeveloped. This part measures 220m east-west by 100m north-south and is estimated to be one quarter of the original area of the bailey. The northern edge of the bailey is defined by the modern road, Castle Hill or Ratten Row, which runs in a 5m deep cutting down into the town centre.
Information from the Pastcape website.