Ancient Monuments

History on the Ground

This site is entirely user-supported. See how you can help.

Carn Alw Hillfort

A Scheduled Monument in Crymych, Pembrokeshire (Sir Benfro)

We don't have any photos of this monument yet. Why don't you be the first to send us one?

Upload Photo »

Approximate Location Map
Large Map »

If Google Street View is available, the image is from the best available vantage point looking, if possible, towards the location of the monument. Where it is not available, the satellite view is shown instead.


Latitude: 51.9707 / 51°58'14"N

Longitude: -4.7112 / 4°42'40"W

OS Eastings: 213858

OS Northings: 233718

OS Grid: SN138337

Mapcode National: GBR CX.L428

Mapcode Global: VH2N7.9Q6M

Entry Name: Carn Alw Hillfort

Scheduled Date: 15 July 1965

Source: Cadw

Source ID: 458

Cadw Legacy ID: PE375

Schedule Class: Defence

Category: Hillfort

Period: Prehistoric

County: Pembrokeshire (Sir Benfro)

Community: Crymych

Traditional County: Pembrokeshire


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. It occupies an outcrop on the northern slopes of the Preseli Mountains which forms an eastern defence overlooking an area c 65m north to south by c 35m protected by a curving stone rampart of 0.8-1m internal height and 2-3.3m external height now spread but though with sections of dry-stone face work surviving in places. The west facing entrance through this is faced by boulders and slabs. Below the rampart on level area ground is a well-preserved chevaux-de-frise consisting of a c40m wide band of stones and boulders, densest around its perimeter, many of which are still upright which was designed to disable an attack at speed by foot or horse. There is a track through this defined by larger stones approaching the entrance. The fort appears to have been the focus for an extensive complex of enclosures & associated features extending about 800m north-west to south-east by 500m which may not necessarily have been contemporaneous.

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 but excludes the surrounding complex of enclosures.

Source: Cadw

Other nearby scheduled monuments is an independent online resource and is not associated with any government department. All government data published here is used under licence. Please do not contact for any queries related to any individual ancient or schedued monument, planning permission related to scheduled monuments or the scheduling process itself. is a Good Stuff website.