Winklebury Camp (SU61355290), an Iron Age 'plateau fort’, now of some 7.6 hectares (19 acres), is situated in the parish of Basingstoke, approximately 1 mile north-west of the town centre of Basingstoke, (fig. 1), though it is now surrounded by housing estates. It occupies a hill of Upper Chalk which has been isolated from the main mass of the North Hampshire Downs by two dry river valleys, one trending south-east, the other north-east. Both are tributary to the R. Loddon. The hill rises to a maximum height of 126 m a.s.l., near the projected line of the western rampart and slopes off gradually to north and south, and more steeply to the south-east. About half a mile to the south of the fort, a tributary of the R. Loddon, now culverted, would have provided the nearest source of water.
Winklebury Camp has suffered from gradual encroachment by the surrounding housing estates, losing the ditch and rampart face to the north and east, and ditch, rampart and a small part of the interior, to the west. Only to the south does any of the bank and ditch survive. In the south-west corner of the fort, in an area protected by the remains of a small copse, a 90 m length of eroded rampart remains to an approximate height of 2 m. There is no ditch fronting this rampart now, but immediately east of the end of the stretch of rampart is the only remaining length of ditch. This extends for some 200 m along the remainder of the south side of the fort, averaging 2 m deep and 5 m wide. It rises in the south-east corner at a causeway, beyond which is another short stretch of ditch which is rapidly lost in house gardens. This causeway is faced by rampart, but there are indications, for example a slight change in the direction of the rampart at this point, that this is in fact a blocked entrance.