In its developed or final form Maiden Castle, some two miles (3.2 km) south-west of Dorchester in Dorset, is an iron age hillfort, of great complexity, which takes in two knolls of a saddle-backed spur of Upper Chalk, the highest point of which is about 440 ft (c. 134 m) above OD. The defences enclose47 acres (c. 18 ha) and consist of three banks and two ditches with an additional bank inserted along most of the south side. There are two entrances, at the east and at the west, each with double openings elaborately defended by outworks. The outstandingly imposing character of Maiden Castle is derived from the size and complexity of these earthwork defences rather than from its altitude or the natural defensive advantages of its position. Ptolemy has been thought to supply a hint as to the ancient name of Maiden Castle. The conventional identification of Roman Dnrchester is with the Durnovania of the Antonine Itinerary. Ptolemy omits that placename, but mentions Dunium in the same region as the one city apparently worthy of mention in the territory of the Durotriges (Geographia I, 103, ed. C Müller (1883)). Dunium was long ago identified with Maiden Castle. This may well be so, although recently Hod Hill and Hengistbury have also been put forward as possibilities. Part of the hillfort lies on the site of a neolithic causewayed enclosure and it also surrounds a unique ‘long-mound’ of the same period, a bronze age round barrow and the foundations of a Romano-British temple and accompanying buildings.