[1][2] The Vale extends south-southwestwards from the coast of the Irish Sea for some 20 miles (about 30 km) forming a triangle of low ground bounded on its eastern side by the well-defined scarp of the Clwydian Range and to the west by numerous low hills.
At its seaward end are the coastal resorts of Kinmel Bay (Welsh: Bae Cinmel), Rhyl and Prestatyn whilst the town of Abergele and city of St Asaph (Welsh: Llanelwy) lie just inland.
Most of the area falls within the modern administrative county (and unitary authority) of Denbighshire and a portion is in Conwy County Borough; much of it lies within the Vale of Clwyd UK Parliamentary constituency.
[4] Like the Cheshire Basin further to its east, it is mostly floored by thick deposits of Permian and Triassic sandstone.
Around St Asaph, late Carboniferous, Coal Measures mudstones and sandstones occur.