The Vale of Clwyd (Welsh: Dyffryn Clwyd) is a tract of low-lying ground in the county of Denbighshire in northeast Wales. 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. The River Clwyd (Welsh: Afon Clwyd) which rises within Clocaenog Forest, southwest of Denbigh, runs the full length of the vale.