The Clwydian Range (Welsh: Bryniau Clwyd; also known as the Clwydian Hills; or simply the Clwyds[1]) is a series of hills in the north-east of Wales that runs from Llandegla in the south to Prestatyn in the north; the highest point is 554 m (1,818 ft) Moel Famau.

The older mudstones and siltstones of the Nantglyn Flags Formation form parts of the west-facing scarp slope and the overlying Elwy Formation, which consists of mudstones and siltstones deposited in deep marine conditions with numerous sandstone beds, forms most of the higher ground.

The Offa's Dyke National Trail traverses the range's high ground from Llandegla to Prestatyn.

The original area was 167 square kilometres (64 sq mi), but in 2011 the area was extended southwards by a further 229 square kilometres (88 sq mi) to include the Dee Valley, Moel y Gamelin, the Horseshoe Pass and Castell Dinas Bran, the towns of Llangollen and Corwen, the Pontcysyllte Aqueduct, Chirk Castle and Valle Crucis Abbey.

There is also one of the few Welsh populations of black grouse and there is a project to conserve the European water vole, which is suffering a large decline in numbers across the United Kingdom.