The sheer diversity of popular magic connected with sacred wells and springs is remarkable. Inseparable from the ancient cults of saints and spirits of place, the natural springs and wellheads of the British Isles have come to be famed loci of healing, divination, and spiritual revelation. Some, possessing long traditions of votive and sacrificial offerings, have assumed powers of spirit-guardianship, or, indeed, divinities of water.  Other such wells are the repositories of eldritch lore connected with the cult of the skull and the Holy Head. Additionally, bodies of magical practice have developed around some wells, serving a variety of magical purposes, including blessings and curses, healings and the dispensation of prophetic power. In almost every case, there is a specific magical relation between the waters as a medium of spirit, and the surrounding features of the land. This monograph examines both the lore of holy wells as well as their associated cultic activities, whether religious or earthed in the practical magic of folk-sorcery.