A hillfort (or hill fort [or hill-fort]) is pretty much just what it sounds like—a fort built into the top of a hill. Generally, hillforts featured an open central area where one or more buildings stood, with multiple ramparts of earth, stone, and/or wood surrounding the central area and proceeding down the hill to exploit the topography and gain a tactical advantage over would-be attackers. Beyond these ramparts was often a ditch or moat.
Historical evidence shows that these structures were first developed in the Late Bronze Age/Early Iron Age, and a number of these ancient hillforts still exist to this day. While the structures were common throughout Europe, here we will be focusing on the hillforts of Britain.
The Why, The How, The Whatnot
There are a number of theories relating to the emergence of hillforts in Britain. Some speculate that they were forts in the truest sense—military installations intended to keep invaders from mainland Europe at bay. Others argue that they may have been built by those same invaders to establish a stronghold on the island.
Still others suggest that the hillforts may have been constructed in response to social changes in the country, brought on by the increased use of iron. (It was the Iron Age, after all.) Because Britain’s prominent iron ore deposits were located in different regions than the tin and copper ore used to make bronze, trade patterns shifted greatly, and power shifted along with them.
Though a good number of hillforts were built during the Bronze Age, most of them were erected between 700 BCE and 43 CE (which coincides with the Roman conquest of Britain). Iron Age hillforts utilizes both natural and manmade defenses.
The ancient Britons built four main types of hillforts: contour, promontory, hill-slope, and plateau. Contour hillforts cut off the upper portion of the hill from the ground below with ramparts that followed the natural contours of the hill itself. Promontory hillforts limited the approach of outsiders through the use of natural features such as cliffs, steep slopes, rivers, etc. Hill-slope hillforts do not enclose the entire hilltop like contour forts do; instead, they are situated on the slope of one side of the hill, with the crest overlooking the structure. Plateau hillforts were built on the flat, level expanses of plateaus.