Ancient Monuments

History on the Ground

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Y Werthyr Hillfort

A Scheduled Monument in Tref Alaw, Isle of Anglesey (Ynys Môn)

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Latitude: 53.3304 / 53°19'49"N

Longitude: -4.4593 / 4°27'33"W

OS Eastings: 236321

OS Northings: 384322

OS Grid: SH363843

Mapcode National: GBR HMCW.VFS

Mapcode Global: WH42C.GKQ5

Entry Name: Y Werthyr Hillfort

Scheduled Date: 14 April 2010

Source: Cadw

Source ID: 1397

Cadw Legacy ID: AN158

Schedule Class: Defence

Category: Hillfort

Period: Prehistoric

County: Isle of Anglesey (Ynys Môn)

Community: Tref Alaw

Traditional County: Anglesey


The monument comprises the remains of a small 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 a single or multiple earthworks of massive proportions. Hillforts 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.

The hillfort is located on a low rounded hill and the earthwork banks and ditches surrounding the summit of the hill are most well-preserved on the S and E sides, with a maximum height of 0.5m. Geophysical survey results indicate that there may be up to eight circular house platforms preserved within the interior of the hillfort, on the eastern side. An entrance is evident on the NE side of the site. The hillfort measures 186m (SW-NE) by 165m (W-E).

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, layout, building techniques and functional detail.

The scheduled area comprises the remains described and an area around, within which related evidence may be expected to survive. It is roughly circular in shape on plan and measures 186m (SW-NE) by 165m (W-E) and is located at SH36320/84305.

Source: Cadw

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