Afon Dyfrdwy is a Site of Special Scientific Interest (SSSI) in the preserved county of Clwyd, north Wales, along the River Dee with the River Dee (England) SSSI in England. The river begins in Snowdonia National Park, Wales. From there, it flows northeast to Corwen, goes eastwards past Llangollen, and continues east through Chester, England. It empties into the Dee estuary, that forms the border between the Wirral Peninsula in north-west England and Flintshire in north-east Wales. The river has been designated a Designated Special Area of Conservation due to its role as a habitat for Atlantic Salmon and Floating Water Plantain.
Buckley Claypits and Commons is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales. It is an important reserve for the great crested newt.
Caeau Pen-y-coed is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Chwarel Pant Glas is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Chwarel Singret is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Coed y Gopa is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Connah's Quay Ponds and Woodland is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Crest Mawr Wood is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Graig Fawr is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales, now in Denbighshire. It is 153 metres high and located near Prestatyn. It is owned by the National Trust.
Graig, Llanarmon-yn-Ial is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Hanmer Mere is a natural lake and Site of Special Scientific Interest in Wrexham County Borough, Wales. The village of Hanmer is at the northern end of the lake. The lake is 18 hectares in extent.
Hendre Bach is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Llyn Bedydd is a small lake in Wrexham County Borough, in northeastern Wales, near the border with England. It is 7 kilometres (4.3 mi) south west of Whitchurch. The lake and the surrounding woodland are designated as a Site of Special Scientific Interest.
Maes Hiraddug is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Maes y Grug is a Site of Special Scientific Interest at Alltami in the preserved county of Clwyd, north Wales.
Pen-y-Cefn Pasture is a Site of Special Scientific Interest in Cilcain, Flintshire, in the preserved county of Clwyd, north Wales. It has been an SSSI since 10 December 1986 as a conservation attempt to protect and preserve the site. Its area is 2.35 hectares. Natural Resources Wales is the body responsible for the site.
Ruabon/Llantysilio Mountains and Minera is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
Stryt Las a'r Hafod is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales, and specifically in Wrexham County Borough. It includes the parks of Bonc yr Hafod and Stryt Las Park.
Marford Quarry is a quarry and a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales. It is managed by the North Wales Wildlife Trust.
