Offa's Dyke Path

Offa's Dyke is an eighth-century earthwork built by King Offa of Mercia to mark the border between his kingdom and the Welsh kingdoms to the west. It is one of the largest ancient monuments in Britain, and the National Trail that bears its name follows it closely for much of its 285 km, making this one of the few long-distance routes that also functions as a history walk.

The path runs through fourteen counties and three national parks, crossing the Wye Valley, the Black Mountains, the remote moorlands of Radnorshire, the Shropshire hills, Clwyd and the north Wales coastal approaches. The southern sections through the Wye Valley are genuinely beautiful, the central sections are lonely and wild, and the north is more pastoral before the descent to the sea at Prestatyn.

For trail runners the route is a good multi-day challenge, typically covered in four to seven days. The terrain is mixed — good paths and bridleways alternate with farmland, the earthwork itself (which is often a clear ridge to run along) and some rough moorland in the Clun Forest and mid-Wales sections. The waymarking is consistent throughout using the acorn symbol.

The trail links the Severn Estuary in the south with the Irish Sea in the north, and on a clear day from the Clwydian hills you can see both — along with much of Wales and the Midlands.

Sedbury to Abergavenny (~80 km): The Wye Valley section. Tintern Abbey, the wooded gorge, the escarpment above Monmouth. One of the most scenically satisfying starts of any National Trail.

Abergavenny to Knighton (~110 km): The Black Mountains section. The Hatterrall Ridge gives superb open ridge running with big views into Wales. Hay-on-Wye is the main town. North of Hay the landscape becomes lonely moorland — Clun Forest, Hergan Hill, the remote Radnorshire hills. Knighton is the geographic midpoint and has a dedicated Offa's Dyke Centre.

Knighton to Llangollen (~80 km): The Shropshire hills and the border country. Long Mynd visible to the east. The dyke itself is well-preserved in sections here. Chirk Castle is a highlight.

Llangollen to Prestatyn (~35 km): The Clwydian Range — Moel Famau, Moel Arthur. The best ridge running of the route and a fine finish above the north Wales coast.

Start: Sedbury Cliffs, near Chepstow. Chepstow has a train station on the Newport–Gloucester line. Car parking in Chepstow town.

Finish: Prestatyn, north Wales. Prestatyn has a train station on the North Wales Coast Line. Regular connections to Chester, Crewe and beyond.

Accommodation is available in most towns along the route — Monmouth, Abergavenny, Hay-on-Wye, Knighton, Montgomery, Welshpool, Llangollen and Prestatyn are the main stops. Book ahead in summer.

Key resupply: Hay-on-Wye, Knighton and Llangollen are the most useful restocking points for multi-day runners. Radnorshire sections have few services.

Best time: April to October. The Black Mountains can be serious in winter. Hay Festival (end of May) means Hay-on-Wye is extremely busy for accommodation.