Badbury Rings is an Iron Age hill fort in east Dorset, England, dating from 800 BC and in use until the Roman occupation of 43 AD. It sits 327 feet (100 m) above sea level. There are two main phases of construction; the first covered 7.3 hectares (18 acres) and was defend by multiple ditches, while the second was more than twice the size, covering 16.6 ha (41 acres) and defended by a single ditch and rampart. Four Bronze Age round barrows indicate an earlier occupation. The fort is situated at the cross of two Roman roads, between Dorchester, Old Sarum (Salisbury), Bath and Hamworthy (Poole).
Dorset fell to the Saxons late in the Saxon invasion of England, being held up by Bokerley Dyke on the Roman Road from Old Sarum. Local historian Roy Carr (2001) has suggested that the Saxons were held off by the threat of an army in the west, perhaps stationed at Badbury Rings. Carr has suggested that such a force could be one of the sources of the legends of King Arthur, and that Badbury could be the "Badon" of the legend of the Battle of Mons Badonicus.
The site, on the dip slope of Cranborne Chase, is now part of the Kingston Lacy estate owned by the National Trust, with free access.
The site is also used for the popular point to point racing by the Portman hunt.