Grimsbury Castle

Grimsbury is a ‘multiple enclosure’ hillfort occupied at least between the third and second centuries bc. Its ramparts follow the contours of the hill on which it stands in order to create its triangular shape. There are three entrances leading into an area covering some eight acres. The main western opening is incurved, with a 394 foot long outer defensive work curving to the north. The other simpler entrances are on the northern and south-west sides. The latter probably led to the fort’s water supply at some local springs. There are also further curved ditch and rampart lines forming an enclosure to the west of the main fort. The name shows that the later Saxon settlers in the region found the earthworks so impressive that they thought they must have been built by the chief of their gods, Woden alias Grim.