Offa’s Dyke is an ancient earthwork between England and Wales. It consists of a ditch and earthen rampart. Offa’s Dyke once extended about 140 miles (225 kilometers) from the mouth of the River Dee in the north to the mouth of the River Wye in the south. Much of it still remains. The best-preserved sections are between Presteign and Montgomery. Offa’s Dyke is named after Offa, king of Mercia, who built it between A.D. 784 and 796 as a defense against the Welsh.
