Maiden Castle is an Iron Age hillfort 1.6 mi (2.6 km) southwest of Dorchester, in the English county of Dorset. Hill forts were fortified hill-top settlements constructed across Britain during the Iron Age.
The earliest archaeological evidence of human activity on the site consists of a Neolithic causewayed enclosure and bank barrow. In about 1800 BC, during the Bronze Age, the site was used for growing crops before being abandoned. Maiden Castle itself was built in about 600 BC; the early phase was a simple and unremarkable site, similar to many other hill forts in Britain and covering 6.4 ha (16 acres).
Around 450 BC it was greatly expanded and the enclosed area nearly tripled in size to 19 ha (47 acres), making it the largest hill fort in Britain and, by some definitions, the largest in Europe. At the same time, Maiden Castle's defences were made more complex with the addition of further ramparts and ditches. Around 100 BC, habitation at the hill fort went into decline and became concentrated at the eastern end of the site. It was occupied until at least the Roman period, by which time it was in the territory of the Durotriges, a Celtic tribe.
After the Roman conquest of Britain in the 1st century AD, Maiden Castle appears to have been abandoned, although the Romans may have had a military presence on the site. In the late 4th century AD, a temple and ancillary buildings were constructed. In the 6th century AD the hill top was entirely abandoned and was used only for agriculture during the medieval period.
Maiden Castle has provided inspiration for composer John Ireland and authors Thomas Hardy and John Cowper Powys. The study of hill forts was popularised in the 19th century by archaeologist Augustus Pitt Rivers. In the 1930s, archaeologist Mortimer Wheeler and Tessa Verney Wheeler undertook the first archaeological excavations at Maiden Castle, raising its profile among the public. Further excavations were carried out under Niall Sharples, which added to an understanding of the site and repaired damage caused in part by the large number of visitors. Today the site is protected as a Scheduled Monument and is maintained by English Heritage.