Offa was an eighth century King of Mercia, a large region of central England, and through alliances with the kings of neighbouring areas, he became the effective King of England. The origin of the dyke, which bears his name, is shrouded in mystery but it appears to have been constructed in response to troubles he had with the local princes in Powys.

The dyke consists of a linear earthwork, which stretched from Prestatyn on the northern coast of Wales right along the approximate line of the modern English/Welsh border to the River Severn near Chepstow. In cross section, it is a substantial structure consisting of a ditch and rampart about 8 metres high and 25 metres wide. Much of the dyke is still traceable today, particularly the stretch between Wrexham and the Wye Valley, and although centuries of farming have destroyed most of the detailed structure it still maintains an impressive presence in places. The Offa's Dyke Path roughly follows the line of the dyke for 177 miles from Prestatyn on Liverpool Bay to Sedbury Cliffs on the Severn Estuary near Chepstow. For about 70 of those miles it directly follows the course of the earthworks and although it is not the longest of the National Trails, it is one of the most varied and attractive.
Immediately after leaving the town of Prestatyn a steep climb leads through a local nature reserve into lush pastureland and through a network of fields and country lanes to the open moorland of the Clwydian Hills. The trail follows the main ridgeline giving splendid views from the 500m elevation. Take the time to explore the hill forts of Moel Arthur and Foel Fenlli as well as the Jubilee Tower on Moel Famau.