NGR: SW 5994 3000
Godolphin Hill and Tregonning Hill are the two high points of the small granitic intrusion which meets the Cornish coast at Trewavas Head to the west of Porthleven. Whilst Godolphin Hill has a rounded profile, Tregonning Hill forms a ridge running south-eastwards. Apart from its outstanding views, Tregonning Hill is remarkable for its diverse archaeological landscape, which includes Bronze Age burial mounds, the Iron Age hillfort of Castle Pencaire, two Iron Age or Romano-British defended settlements or Rounds, a well preserved mediæval field system, a late 18th century watch house, and a quarry where John Wesley is alleged to have preached. In addition, this is the place where china clay was first extracted by William Cookworthy in the middle of the 18th century.
Castle Pencaire, on the summit of Tregonning Hill, by tradition an abode of giants, is a hillfort of Iron Age date, oval in shape and defined by a pair of ramparts and ditches with entrances on both the east and west sides. A number of hut circles have been identified in the interior, but this has been heavily disturbed by later activity including mining and prospecting and these features are by no means clear. The site is bisected by a modern boundary, and a 20th Century War Memorial, constructed of stone from the ramparts, has been built atop the ramparts on the western side.
Strategically sited on lofty hilltops commanding wide views over the surrounding landscape, hillforts were not necessarily intended primarily for defence, although they may have sometimes served that purpose. More likely they were centres of trade and served as a focal point for community gatherings and ceremonies, the impressive banks and ditches being a means of displaying status and power. It is not known whether the round houses in the interior represent evidence for a permanent settlement – occupation may have been sporadic or seasonal, or associated with specific activities taking place at the site.
On the north-eastern slopes of the hill are two smaller defended farmsteads or rounds; the rampart of the western one has been partially removed and the remainder survives, fossilised into the modern field pattern, whilst the better preserved eastern enclosure lies in moorland and is complete, with traces of several hut circles in the interior and a causewayed track leading to the entrance on its south-eastern side. These two settlement sites may be broadly contemporary with the hillfort, but Rounds were constructed and occupied for over a thousand years and they may equally represent a later phase of occupation when the hillfort had been abandoned.
A system of strip fields and ridge and furrow extending over the northern slopes of the hill is probably the result of mediæval rather than prehistoric farming. On the ridge to the south of Castle Pencaire is a Bronze Age barrow in which was discovered a Roman coin hoard indicating activity in the area both before and after the period during which the hillfort would have been at its height.
Tregonning Hill is protected as an Scheduled Monument. Public footpaths from Balwest and Tresowes Hill give access to the hill, and much of the ground here is Access Land.