The Afon Dyfrdwy (River Dee in English)is about 70 miles long, it rises below Mynydd Dduallt(662m)in the hills above Llanuwchllyn, Gwynedd, Mid Wales before it passes through Llyn Tegid (Bala Lake) and then flows north via Llangollen and Chester, and discharges to the sea into an estuary between Wales and the Wirral in England