Mae'r cais yn cynnwys cymunedau Dyffryn Ogwen; Dinorwig; Dyffryn Nantlle; Cwmystradllyn a Chwm Pennant; Ffestiniog a Phorthmadog; Abergynolwyn a Thywyn. Mae'r cais - dan arweiniad Cyngor Gwynedd - yn bartneriaeth rhwng nifer o sefydliadau gan gynnwys Parc Cenedlaethol Eryri, yr Ymddiriedolaeth Genedlaethol, Prifysgol Bangor, Llywodraeth Cymru, Cadw, Comisiwn Brenhinol Henebion Cymru a'r Amgueddfa Genedlaethol.
The application includes the communities of Dyffryn Ogwen; Dinorwig; Dyffryn Nantlle; Cwmystradllyn and Cwm Pennant; Ffestiniog and Porthmadog; Abergynolwyn and Tywyn. The bid-led by Gwynedd Council is a partnership between a number of organisations including Snowdonia National Park, the National Trust, Bangor University, the Welsh Government, Cadw, Royal Commission on the Ancient and Historical Monuments of Wales and the National Museum.