Offa's Dyke

Offa's Dyke is a massive earthwork between England and Wales, running from the estuary of the River Dee in the north to the River Wye in the south.

The earthwork is widely attributed to Offa, King of Mercia in the 8th century. At the time it was used as a defensive measure against the depredations of the Welsh and as a boundary between England and Wales. It is not known to what extent Offa was indeed responsible for building the dyke - important parts of it may date from earlier periods.

Offa's Dyke is a linear earthwork which roughly follows the Welsh/English boundary. It consists of a ditch and rampart constructed with the ditch on the Welsh-facing side, and appears to have been carefully aligned to present an open view into Wales from along its length. As originally constructed, it must have been about 27 metres wide and 8 metres from the ditch bottom to the bank top.

It is one of twelve designated National Trails. It is the only national trail to follow a man-made feature. It runs 182 miles from Prestatyn in the north to Sedbury, near Chepstow in the south. Men from the border country along the Mercian (English) side all had to contribute: they could send food or they could build 128cm of dyke.

North Wales, Snowdonia and Offa's Dyke

Offa's Dyke (Tempus History & Guide S.)