Please note: There is no public access to this monument. Access only by prior agreement with the Bodorgan Estate.

1. Anglesey Inventory 1937. LLANGADWALADR pp87-88

TWYN-Y-PARC PROMONTORY FORT, situated on a rocky coastal headland 3 m. S.S.W. of the church. The promontory rises to a maximum height of 100 ft. and in most places has precipitous cliffs to the sea. The defences are concentrated on the neck, where a massive major rampart and two subsidiary banks isolate the promontory from the mainland. Additional defences, in the form of a wall on an artificial terrace, have been made on the less precipitous N.W. side. The main rampart runs in a slight curve across the narrowest part of the neck; its S.E. end abuts on a steep cliff and its N.W. end stops short of the edge of the slope to allow of an entrance. It is about 75 yards long, 18 ft. high, and composed of stone with some earth. On the landward side of this rampart is a small entrenchment about 75 yards long running from the W. side of the isthmus and terminating on a small outcrop. On the E. side of the neck, 10 yards from the foot of the main rampart and parallel with it, is a similar small entrenchment, about 40 yards in length. It stops short in line with, but about 15 yards behind, the end of the other outer rampart, forming an overlap entrance.

The defences on the N.W. side consist of a wall on a terrace artificially built up with stones and earth in the gaps of the rock on the irregular rocky slope which, for a length of about 150 yards above the creek called Porth Fain, is less precipitous than elsewhere. Two or three stones of the wall on the outer edge of this terrace still remain in situ. The elaborate defence of the promontory at this point was doubtless due to the need for protection from assault from the creek, which formed an excellent landing-place for small craft. (See also p. lxx.) Condition—Good, particularly of main rampart.

2. Ordnance Survey Record card: NAR SH36SE1

A later Prehistoric style fort formed by strong ramparts cut across the narrow neck of a long and straggling cliff-girt promontory. The promontory is roughly 350m deep and at most 100m wide. It has an area of about eight acres or 3.2ha, although most of this is beset with crags and only the eastern part, immediately within the ramparts, is though suitable for settlement.
The main rampart, a massive 2.4m high bank, runs across the 70m wide neck with an entrance gap at the northern end. There are two outer ramparts or ruined walls, on the north side of the neck and only one to the south where a crag rises on the landward side. The entrance winds between these outer ramparts. Desultory diggings in the late 1930s produced rim sherds of a third-fourth century Roman mortaria, an iron spearhead and a crucible fragment bearing traces of copper. These finds were made in the area immediately within the ramparts.

3. Cadw: Scheduled Monument Entry for AN049

Promontory isolated from mainland by massive major ramparts and two subsidiary banks. The main bank runs across the neck of the promontory from the S side and stops just short of the N side; the short gap between the end of the bank and the cliff may have been the entrance. The bank is about 70 m long, 8 m wide and 2.5 m high; there is a small outer ditch. The outer defences consist of two banks which just overlap. The bank to the NW is about 70 m long and between 0.5 and 1.0 m high from the inside, and between 1.5 and 1.8 m high from the bottom of the external ditch. On the E side is a similar low bank, about 36 m long and 1.25 m high from the bottom of the external ditch. Along the NW side of the fort a strong stone wall some 135 m long has been constructed along the top of the cliff edge. Some of this wall is falling over the edge, but much of the bottom course remains. Some finds of Roman date have been found. The monument is of national importance for its potential to enhance our knowledge of Prehistoric/ Romano British settlement and defence. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits. The structures themselves may be expected to contain archaeological information concerning chronology and building techniques.

4. The Gwynedd Archaeological Trust (PRN 3024) note; ‘In the late 1930s, Meyrick conducted some very minor excavations, just inside the rampart. He recovered finds such as a sherd of mortarium dating to the third or fourth century AD, a group of coins dating from the late-third and early-fourth centuries AD, as well as an iron spearhead.’

5. Royal Commission field visit (19/09/2024) summary:

The Twyn-y-parc headland forms a projecting south-western promontory overlooking the wide estuary of the Afon Cefni and Malltraeth Sands along the south side. The coastal extremities here are eroded into a series of promontories and bays, of which Twyn-y-parc is one of the highest and most impressive, reaching 30m O.D. defined by a series of crags and hillocks. It is matched by nearby prominent, but undefended, coastal headlands at Dinas-lwyd to the east and Dinas Trefri to the north, both of which may also have been foci for human activity in prehistory and early history.

Twyn-y-parc coastal promontory fort measures some 380m south-west to north-east by 90m, from the outer edge of the eastern promontory defences to the high water mark above the coastal rocks which fringe the headland. The interior encloses 3.13 hectares. The rock outcrops, gullies and canyons appear to have been expertly harnessed to provide interior ‘roads’ and areas for settlement in later prehistory.

The eastern defences:

The main defences were built on the landward neck on the east side. Complex outer and inner gateways give access to an interior terraced and levelled area. The outermost defences comprise, on the north side, a 42m long rampart with a rock-cut outer ditch which runs up from the coastal inlet of Porth Fain; there is an active spring outside this rampart on the north side, just above the inlet. On the south side, a rock face has been cut back to form an outer ditch with an inner rampart below the main rampart. The rocky edge of a bedrock plateau to the east of the defences may also have been modified to guide visitors in towards the outer gate.

These outer ramparts appear to provide an overlapping and baffled entrance approach, guiding visitors in towards the main inner rampart. This inner rampart runs for 70m and curves around from west to south, overlooking all approaches. Its outer face towers 2.5-3m above the heads of visitors. It is surmounted by a 1m wide stone wall, and has a stepped rear face. Access into the hillfort was apparently gained around the north-west terminal of this rampart where large structural slabs are exposed in the path.

The interior:

Once inside, there is a wide, levelled, terraced area at the foot of the main outcrops which is likely to have been artificially enhanced for settlement. Around the north side a narrow, walled coastal terrace hugs the outcrop and runs some 80m west of the gateway providing access to Porth Fain inlet; in places the terrace edge is defined by upright slabs. Although this walled terrace may have prehistoric origins, its main purpose appears to have been to serve a stone slab quarry on the north side of the promontory, probably in post-medieval times.

A main interior feature of the promontory fort is an impressive inner gateway leading up from the eastern terrace, clearly defined by two natural outcropping rock bluffs with a broad 3m-wide road or ‘cartway’ between them. These rock bluffs take the role of gateway terminals, and the neat edges of the cartway suggest the rock-cut passage at least has been improved. Fragmentary stone walling can be seen around the northern ‘terminal’ outcrop, suggesting there may once have been walling or a timber superstructure here.

From this inner gateway two natural canyons or ‘roads’ diverge and lead visitors up and into the rocky interior. Despite the crags and bluffs, there are expansive terraces of level grassy ground within the promontory which would have provided ample space for buildings and livestock. There are few discernible interior features of note, apart from some prominent boulders at SH 3682 6490 which may have provided nooks for shelter or ceremony. A conspicuous propped slab and boulder, not naturally placed, at SH 3675 6484 may also be a structural or ceremonial feature.

Visited by Toby Driver and Louise Barker for the Royal Commission, 19th Sept 2024

References:

RCAHMW (M). 1937. An Inventory of the Ancient Monuments in Anglesey. HMSO, London. Pp. 87-88
Hughes in Archaeologia Cambrensis 94 (1939), 98-9
Transactions of the Anglesey Antiquarian Society & Field Club for 1945, 21-2
Lynch 'Prehistoric Anglesey' (1970), 232-3

Site Record

Twyn y Parc Coastal Promontory Fort