Ancient Monuments

History on the Ground

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

Slate Gwaliau at Felin Fawr, Penrhyn

A Scheduled Monument in Llandygai (Llandygái), Gwynedd

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: 53.1769 / 53°10'36"N

Longitude: -4.074 / 4°4'26"W

OS Eastings: 261481

OS Northings: 366428

OS Grid: SH614664

Mapcode National: GBR 5S.3SZ6

Mapcode Global: WH54G.DD6W

Entry Name: Slate Gwaliau at Felin Fawr, Penrhyn

Scheduled Date: 3 August 1998

Source: Cadw

Source ID: 3959

Cadw Legacy ID: CN297

Schedule Class: Industrial

Category: Wall

Period: Post Medieval/Modern

County: Gwynedd

Community: Llandygai (Llandygái)

Traditional County: Caernarfonshire


The monument consists of an exceptionally well preserved group of gwaliau or slate-makers' booths which were used in conjunction with the important Felin Fawr slate mills of Penrhyn Quarry. There are six booths in a curving row, with mono-pitched roofs, open-fronted to the east. An unusual awning survives to the fronts of some of the booths. A stock of slate slabs is left at the north end. The mill complex produced slabs and most roofing slates were made at the quarries themselves. The gwaliau here may have trimmed slates broken in transit or remainders from the slab mills, but it is likely that they operated as a 'showcase' for visitors to the quarries.

Penrhyn was the largest slate quarry in the world by the early nineteenth century. It was connected to Port Penrhyn by a railway built in 1801, and the Felin Fawr mills were established by 1803 where the railway crossed a river.

The monument is an exceptionally well-preserved and prestigious example of these key slate quarry structures and is of national importance for its potential to enhance our knowledge of construction practices. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits.

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

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.