All National Trail Guides contain: Ordnance Survey 1:25 000 maps covering the entire route. A detailed description of the route and sites of interest that lie along it. Background information on landscape, archaeology, wildlife and local history. Full colour photographs. Information on public transport, accommodation, facilities and useful services and organizations. Offa"s Dyke South covers the southern part of the route, 80 miles (128 km) from Chepstow on the Severn Estuary to Knighton. A spectacular walk, at first following the River Wye to Monmouth and then crossing the Black Mountains to reach the river again at Hay-on-Wye before continuing northwards through the unspoilt hills of the Welsh marches.