Llangollen is a town and community, situated on the River Dee, in Denbighshire, Wales. Its riverside location forms the edge of the Ber…Llangollen is a town and community, situated on the River Dee, in Denbighshire, Wales. Its riverside location forms the edge of the Berwyn range, and the Dee Valley section of the Clwydian Range and Dee Valley Area of Outstanding Natural Beauty, with the easternmost point of the Dee Valley Way being within the town. It had a population of 3,658 at the 2011 census.