During the 8th century, King Offa of Mercia ordered a great dyke to be built, stretching from sea to sea, to mark the western boundary of his kingdom with Wales. In places it is still visible as a bank up to 25 feet high with a deep ditch alongside. Beginning at Chepstow on the Severn Estuary, Offa's Dyke Path follows the course of this ancient earthwork to Prestatyn on the coast of North Wales. It passes through scenery of great beauty and variety ranging from the woodlands of the spectacular Wye gorge to the windswept ridges of the Black Mountains and from the rolling hills and secluded valleys of mid-Wales to the heather-clad Clwydian Hills. Along the way it visits a succession of historic border towns and attractive villages including Monmouth, Hay-on-Wye, Knighton, Montgomery and Welshpool.

There is much of historic interest along the trail: Chepstow Castle, the first stone fortress built in Wales; the picturesque ruin of Tintern Abbey on the banks of the Wye, founded in 1131 for monks of the Cistercian Order; the 13th century gatehoused bridge at Monmouth; the imposing stronghold of White Castle with its high curtain walls and deep moat; the castle-like church of St Cadoc's at Llangattock Lingoed, where villagers sheltered in times of conflict; magnificent Powis Castle at Welshpool; the drum-towered Marcher fortress of Chirk Castle and the hilltop fort of Dinas Bran overlooking Llangollen.