Ancient Monuments

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Craig yr Aderyn Hillfort

A Scheduled Monument in Llanfihangel-y-Pennant, Gwynedd

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Latitude: 52.6422 / 52°38'32"N

Longitude: -4.0043 / 4°0'15"W

OS Eastings: 264483

OS Northings: 306828

OS Grid: SH644068

Mapcode National: GBR 8W.6LQ4

Mapcode Global: WH570.GVF8

Entry Name: Craig yr Aderyn Hillfort

Scheduled Date:

Source: Cadw

Source ID: 2472

Cadw Legacy ID: ME075

Schedule Class: Defence

Category: Hillfort

Period: Prehistoric

County: Gwynedd

Community: Llanfihangel-y-Pennant

Traditional County: Merionethshire


The monument comprises the remains of a hillfort, which probably dates to the Iron Age period (c. 800 BC - AD 74, the Roman conquest of Wales). Hillforts are usually located on hilltops and surrounded by single or multiple defensive banks of massive proportions. This example has been built against the south-eastern flank of a steep-sided local summit, at one side of a col high on Craig yr Aderyn. It has an inner rampart c.90m long on the south side and c.60m long on the east, which fades out at either end where the ground becomes steep enough to provide natural protection. This is now quite considerably grass-grown, though it may have supported a stone wall; it stands c.4.5m high externally, but only c.0.6m high internally, reflecting the slope of the hill. A slightly inturned entrance through the eastern side retains footings of a stone wall on each side. Quite probably at a later date, though there is no direct evidence, a further enclosure surrounded by a massive stone wall of similar scale to the original was added to its eastern side, extending the line of the southern defence by c.45m eastwards and swinging round for c.90m to end on the edge of the northern precipice. This rampart has an elaborately inturned entrance on the south with an ascending passage-way c.3m wide. Outer defences added to this take the form of a small bank along the east side and a small stone wall along the whole of the south side, which has seen later modification to include pens and shelters. A grassy shelf within the inner southern defences shows signs of habitation, though no traces of hut circles can be identified; finds of Romano British pottery are recorded from the site. The main fort encloses 0.8ha and the annexe 0.4ha. Hillforts generally must have formed symbols of power within the landscape, while their function may have had as much to do with ostentation and display as defence. This example is unusual in being virtually invisible from the valley below, though it has wide views both towards the coast and up the valley routes running inland to east and north-east.

The monument is of national importance for its potential to enhance our knowledge of later prehistoric defensive organisation and settlement. The site forms an important element within the wider later prehistoric context and within the surrounding landscape. The site is well preserved and retains considerable archaeological potential. There is a strong probability of the presence of evidence relating to chronology, building techniques and functional detail.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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