A World Heritage Site is an area or location that has been selected by the United Nations Educational, Scientific and Cultural Organization (UNESCO).  It is an area with special significance in terms of its culture, history, science, or other factors.  It is legally protected by international agreements.   

Examples include the Taj Mahal, the Pyramids, Jodrell Bank, Stonehenge, the Great Wall of China and a number of other sites around the world. 

In the UK there are 33 World Heritage Sites.  World Heritage UK is an organisation set up in 2015 to undertake networking, advocacy and promotion for the UK’s World Heritage Sites, and the Tentative List Sites progressing towards WHS status. For more information, visit the World Heritage UK web site:  World Heritage UK

UNESCO is an agency within the United Nations responsible for promoting peace, social justice, human rights and international security.  It does this by getting countries across the world to cooperate on educational, science and cultural programmes.   

More information about the Slate Landscape of Northwest Wales World Heritage Site and other World Heritage Sites can be found on UNESCO's website.                                                                                                                                 

Yes, this is proof of the historic importance of Wales.  More information can be found on these links:  

  • The Castles of Edward 1st are an example of confident military colonial architecture.  One of them, Caernarfon  Castle is located immediately next to the Slate Quay from where thousands of tonnes of slate were exported around the world. It became a World Heritage Site in 1986 

  • The Blaenavon Steelworks site  near Abergavenny was listed in 2000 because of its huge contribution to the Industrial Revolution. 

  • Pontcysyllte Aqueduct  near Wrexham was designed by Thomas Telford. After it was completed in 1805, it was the highest aqueduct  for canal boats in the world. It became a World Heritage Site in 2009. 

Gwynedd Council led the application in partnership with Cadw, Welsh Government, Snowdonia National Park Authority, the Royal Commission on the Ancient and Historical Monuments of Wales, Bangor University, the National Trust and the National Slate Museum.  

The partners formed a Steering Group and two sub-groups.  One sub-group is responsible for planning, conservation, and management, and the other is responsible for economic development. Experts in heritage, conservation, engagement, and public relations are working on specific tasks. The project leading up to the designation has been managed by a small team from Gwynedd Council's Economic Development Department, Cadw and the Royal Commission on  the Ancient and Historical Monuments of Wales. 

The development of the application was a strategic priority set by Gwynedd Council, who has been responsible for leading on the application. All the partners in the initiative have contributed financially or through practical means, and funding has been received by Gwynedd Council through schemes such as the National Lottery Heritage Fund, the Snowdonia Partnership Fund, Arloesi Gwynedd Wledig and the European Union.  The Wales Slate Partnership, a group representing the public, private and voluntary sectors within the industry, has provided significant specialist support and some financial support.

It is an outstanding example of a cultural landscape formed by centuries of quarrying, working and transporting slate to global markets. This is our Statement of Outstanding International Value. The slate landscape displays all relevant elements of the industry in visible, readable and accessible forms: 

  • Excavation – quarries and caverns 

  • Processing – slate mills, open fronted splitting areas (gwaliau), workshops 

  • Transportation – railways, ports, tramways 

  • Dwellings – communities and grand houses of owners, places of worship, libraries and hospitals 

  • End use – roofing, gravestones, pillars for fencing, carved and decorative slates 

  • The transition from an agricultural to an industrial society 

  • Reinforcing minority culture by international industrialisation 

  • The world's largest exporter during the mid-19th Century 

  • Transferring technology, expertise, and people worldwide 

Protect, conserve, enhance and communicate the important qualities of the area in order to reinforce cultural distinctiveness and strengthen the Welsh language, and become an important driver for economic regeneration and social inclusion. 

  • A thriving regional economy 

  • Vibrant and living communities proud of their community and heritage 

  • High quality, skilled employment 

  • Higher value tourism sector, all year round 

  • Continuation of the slate industry 

  • A sustainable and living landscape 

  • Celebrate the role of our slate heritage in the world 

  • Protect and enhance physical heritage

2009  - Presentation of the Wales Slate application to the Department of Culture Media and Sport (DCMS) at Westminster. 

2009 – UK government places the application on the tentative list of possible sites. 

2012 – The tentative list is presented to UNESCO. 

2010 to 2015 -  All Partners work together to develop the technical evaluation of the site. 

2015 – Presentation of the technical evaluation to DCMS for consideration by a panel of experts. 

2018 – DCMS announce that this application will be the next to be presented to UNESCO 

2019 – Cyngor Gwynedd’s Cabinet approve the final version of the Nomination; this is also approved by DCMS. 

January 2020 – Presentation of the final version of the Nomination to UNESCO. 

September 2020 – In depth site visit by an UNESCO assessor. 

July 2021 – Announcement that the designation was successful.

The production and adoption of a Management Plan is a requirement of UNESCO. It provides an overall framework of objectives. The draft Management Plan was consulted on during August / September 2019. The comments received were been fed into the final plan which was submitted to UNESCO as part of our application. There are 5 themes within the Management Plan: 

  • Governance and Management,  

  • Slate Landscape Care,  

  • Sustainable Development,  

  • Slate Landscape Enjoyment,  

  • Slate Landscape Learning 

In addition, a local management plan will be prepared for each element (area) of the World Heritage Site. 

The designation will not add additional planning constraints to current planning policy - designated and proposed world heritage sites are a material planning consideration within Gwynedd's planning policies. Supplementary Planning Guidance has been developed relating planning policy to the Designation areas. 

A new Destination Management Plan will soon be developed by Gwynedd Council, which will look at sustainable and sensible management of tourism growth, as well as supporting sustainable and living communities. The nomination will attract visitors with a particular interest in heritage, and studies prove that these are visitors who tend to visit outside traditional holiday periods, and tend to spend more during their visit. 

We have developed a hub and spoke model to move visitors around the area, take the pressure off the traditional main sites, and also to spread the economic benefit. The Interpretation Strategy encourages visitors to 'follow the story' around the area, and beyond the boundaries of the World Heritage Site safley and to accessible sites. 

The Welsh language is a theme that runs throughout the nomination document and is identified in the Management Plan. 

It will not increase public access across the site, and therefore will not add a burden to landowners to protect / preserve structures. Being within the boundary of a World Heritage Site does not mean that access to all parts of the site must be allowed. 

The designation of World Heritage does not mean that the public has access to private property. The area contains relict quarries and active railways, which have their own health and safety requirements. Public access is also not appropriate in all areas to protect fragile historic assets and in some cases to enable commercial activities. 

We are working with Snowdonia Active on developing messages and a security campaign for the slate landscape to complement the AdventureSmart.uk  campaign. 

Although no additional funding comes directly with the Designation, we hope that groups will be able to use the Status in support of any grant applications.

Community events have been held across the area over the past few years, regular articles in Newyddion Gwynedd which is circulated to every property in Gwynedd and specific Consultation sessions on a Draft Management Plan were held during August - September 2019, with drop in sessions and an opportunity to complete an online questionnaire on the Gwynedd Council website. 

We have also held online information events and include a number of community groups in our work.



Size in inches 


Size in inches 


26 x 16 


24 x 14 


24 x 12 

Small Duchesses 

22 x 12  

Narrow Duchesses 

22 x 11 

Wide Countesses 

20 x 12 


20 x 10 

Small Countesses 

18 x 10  


18 x 9 

Wide Ladies 

16 x 10 

Large Ladies  

16 x 9 


16 x 8 

Small Ladies 

14 x 8 

Narrow Ladies 

14 x 7 

Double Slates 

12 x 6 

Single Slates 

10 x 5