Slate Landscape of Northwest Wales

The Slate Landscape of Northwest Wales was inscribed on the UNESCO World Heritage List on 28 July 2021, at the 44th session of the World Heritage Committee (reference 1633). It recognises the quarries, mines, settlements and transport routes of the Welsh slate industry in Gwynedd.

What it covers

The property is made up of six component areas across the mountains of Snowdonia (Eryri) and the valleys and coast around them. They include major quarrying centres such as Penrhyn near Bethesda and Dinorwig near Llanberis, and other slate districts with their villages, chapels, railways, inclines and harbours.

Why it was listed

UNESCO accepted the site under two criteria:

• Criterion (ii): the landscape shows an interchange of developments in technology and architecture. Welsh quarrying methods and skilled workers were exported from the 1780s into the early 20th century, notably to slate industries in the United States, continental Europe and Ireland.
• Criterion (iv): it illustrates how an agricultural upland was transformed by industry during the Industrial Revolution.

UNESCO frames the industry's period of global dominance as 1780 to 1940. By the late 19th century the region produced about a third of the world's roofing slates and architectural slabs.

Roofing significance

Welsh slate roofed terraced houses, factories and grand buildings during rapid urban growth, in Britain and abroad. Its light, thin, regular slates also encouraged the shallow-pitched roofs typical of Georgian architecture. The inscription is one of very few World Heritage Sites defined chiefly by the production of a roofing material.

Management

Gwynedd Council leads the management of the site with partners. Slate is still quarried in the area, notably at Penrhyn, and the landscape includes active workings alongside heritage sites such as the National Slate Museum in Llanberis.