Hill forts are earthworks that are found in many parts of Britain and Ireland. They were built by the prehistoric inhabitants of the islands. Most of those still remaining date from about 200 B.C. The forts were placed at strategic points, generally on hilltops. They were built as circular walls of earth reinforced by fences made of tree trunks or stones and protected by deep ditches. They varied in size. Some had ditches and stockades (fences) to protect cattle, and pits and raised granaries for storing grain. Place names that include caer, dun, or burgh, or variants of these words, indicate the site of a former fort. Examples are Caer Caradoc, Carlisle (originally called Caer Luel), Donegal (still called Dún na nGall in Irish), London, and Edinburgh (originally called Din Eidyn, and still called Dùn Èideann in Scottish Gaelic).
Hill forts were constructed and used up to the time of the Roman invasion of A.D. 43. Most of them were abandoned after the Roman occupation. Hill forts still existing include Badbury Rings, in Dorset, one of the largest.
