Designated in 1985 as the Clwydian Range AONB, and expanded to its current extent in 2011, the Area of Outstanding Natural Beauty includes: medieval field systems, open heather moorland, prehistoric hillforts, limestone crags, broad leaved woodland, wooded valleys, and farmland.

The mainly Silurian Clwydian Range supports rounded, heather-clad hilltops which provide habitats for scarce flora and fauna and are home to Iron Age hillforts.

[4] The AONB is additionally known for its lack of light pollution and home to "cherished" dark skies for dark-sky gazing for astronomers, enthusiasts and casual observers.

The broad upland range of rounded, heather-clad open hills runs from Nant y Garth in its south (bordering the Dee Valley section), and up to the carboniferous limestone hillside[10] on outskirts of Prestatyn to the north.

Notable natural features include: Chwarel Pant Glas, a site of importance for the study of structural geology, Aber Sychnant's limestone pavements, and the Minera cave system.

The area was later submerged in a shallow tropical sea, forming the limestone deposits in modern-day Eglwyseg, Eryrys, Graig Fawr, Moel Hiraddug, Prestatyn Hillside, Loggerheads, and Bryn Alyn.

[10] This ash smothered the marine life present in the shallow sea, which was home to organisms such as; brachiopods, corals, crinoids, fish, goniatites, and trilobites.

[10] Upon the retreat of the glaciers around 14,000 years ago, they left behind erratic boulders, sands, gravels and clays which form hummocky terrain in areas such as the valley of the River Wheeler.

[10] Along with the rest of Wales, the Clwydian Range and Dee Valley have a maritime climate, in the north temperate zone, with the predominant winds being the westerlies blowing in from the Atlantic Ocean.

Snow is comparatively rare near sea level in Wales, but much more frequent over the hills of the range, and the uplands experience harsher conditions in winter than the more low-lying parts.

Using data between 1981 and 2010, provided by a nearby Met Office weather station, located in Hawarden Airport, Flintshire, in the plains to the east of the range and not on the coast.

[18] The limestone grasslands of the AONB support habitats for flora such as cowslip (Primula veris), rockrose (Cistaceae), autumn gentian (Gentianella amarella) and orchids (Orchidaceae).

[17][19] The broadleaved woodlands of the AONB are home to dormice, and the rivers Dee and Alyn provide a suitable habitat for freshwater pearl mussels, Atlantic salmon, and otters.

[27] Between 2012 and culminating in an exhibition in 2018 at Loggerheads Country Park, the Clwydian Range Archaeology Group (CRAG) established in 2011,[28] surveyed and excavated the area surrounding Moel Arthur for a number of years.

[13] The earliest evidence of human settlement in the modern-day AONB exists at Tremeirchion, in the Ffynnon Beuno Caves, where the discovery of stone tools dated to between 30 and 40,000 years ago, was made.

[13] Other caves along the Clwydian Range reveal various finds from various times, of animals once inhabiting the area, including the mammal bones of spotted hyenas, mammoths, and lynxes.

[citation needed] Ritual and burial monuments from the Bronze Age are present in significant quantity in the AONB, prominently placed on summits in the area.

[4] During the Industrial Revolution, mining for lead and coal, and the production of iron was increasingly present in the areas east of the AONB near the city of Wrexham and the slopes towards it.

[34] The Clwydian Range was designated as an Area of Outstanding Natural Beauty in 1985 by the Secretary of State for Wales Nicholas Edwards MP, under the National Parks and Access to Countryside Act 1949, covering 158 km2 (61 sq mi) until its extension.

[33] In 2005, a Pathfinder partnership was set up by the three local authorities of Denbighshire, Flintshire, and Wrexham, with the Countryside Council for Wales (CCW) to consider whether an AONB extension into the Dee Valley would be beneficial.

[33] The Countryside Council for Wales expressed its proposal to extend the Clwydian Range AONB[37] to incorporate sections of the Dee Valley to recognise the area's "outstanding natural beauty".

The CCW hosted a four-month consultation in October 2010, and following its end on 31 January 2011, it received 314 responses mainly over concerns of new regulations imposed on landowners.

It would then be the responsibility of the Welsh Assembly Government Minister for the Environment Jane Davidson to make the final decision on the proposal as early as March 2011.

The CCW stated that the proposed extended area is of "outstanding quality, nationally and internationally important for their natural beauty and equally worthy of protection as an AONB".

[42][43][44] The newly added Dee Valley area, includes Eglwyseg escarpment, Moel y Gamelin, Esclusham Mountain, the Horseshoe Pass and Castell Dinas Brân, the towns of Llangollen and Corwen, the Pontcysyllte Aqueduct and Canal World Heritage Site, Chirk Castle, and Valle Crucis Abbey.

[54][55] In June 2023, the Welsh Government commissioned Natural Resources Wales to investigate a potential designation of the area into a national park, involving data and evidence gathering and meeting with local communities, with a decision expected by 2026.

[59][60][61] The partnership also includes other key stakeholders, such as community councils, statutory agencies, landowners, farmers, and members representing conservation and recreation interests and groups.

The same act places a duty on public bodies; including private utility companies to respect efforts made to conserve, protect, and enhance the AONBs natural beauty.

The A5, a historically important and mainly scenic route today, passes through the Dee Valley in the South, and the A494 goes through the AONB at its centre, connecting Ruthin and Mold.

[4] Bus services operate between the main towns within and next to, the AONB; such as the TrawsCymru T3 Dolgellau to Wrexham route which travels through Corwen and Llangollen along the Dee Valley.