Beacon Hill is probably an early 13th century earth and timber ringwork siege castle, founded in the minority of King Henry III. In 1216-17, the castle provided a base for supporters of Prince Louis of France, to check the activities of the besieged Pickering Castle garrison. The hill was modified, by cutting back its sides to create a steep sided, roughly oval mound topped by a low bank, encased by a ditch and an outer bank. The structural remains of at least two mid 20th century Royal Observer Corps posts, have damaged the earthworks. Fortification were known to be built in the mid 12 century Anarchy, in the reign of King Stephen and Beacon Hill could be an example of one.