Ponter's Ball Dyke is a linear earthwork located near Glastonbury in Somerset, England. It crosses, at right angles, an ancient road that continues on to the former island of dry land in the Somerset levels surrounding Glastonbury Tor. It consists of an embankment with a ditch on the east side. It is built across the ridge of land between Glastonbury and West Pennard. Both ends of the ditch and dyke disappear into moorland, formerly swamps.