Hatfield Forest in neighbouring Hatfield Broad Oak has been a Royal Hunting Forest from the time of the Norman kings. The forest is open to the public and covers of woodland, grassland with trees, lake and marsh. Portingbury Hills in Hatfield Forest is suggested to be a defended settlement or farmstead dated to the Iron Age. According to the National Trust The main rectangular mound is approximately and is surrounded by a ditch 25 to 35 feet wide, with a flat top..