Wat's Dyke
Wat's Dyke (Welsh: Clawdd Wat) is a 40-mile (64 km) linear earthwork running through the northern Welsh Marches from Basingwerk Abbey on the River Dee estuary, passing east of Oswestry and on to Maesbury in Shropshire, England. It runs generally parallel to Offa's Dyke, sometimes within a few yards but never more than three miles (5 km) away.