HOLYWELL (Tre'ffynnon, well-town), a small town of Flintshire, north Wales, situated on a height near the left bank of the Dee estuary. Pop. of urban district 3,423. The parish church has some columns of an earlier building, and a strong embattled tower. The remains of Basingwerk abbey (Miles glas, green field), partly Saxon and partly Early English, are near the L.M.S. station about 2 m. from the town. It was used as a monastery before 1119, and in 1131 Ranulph, earl of Chester, introduced the Cistercians. It was dissolved in but used in after years as a Roman Catholic burial place. Scarcely any traces remain of Basingwerk castle, an old fort. St. Wini fred's well is a place of pilgrimage for Roman Catholics. The well itself is covered by a fine Gothic building, said to have been erected by Margaret, mother of Henry VII., with some portions of earlier date. In 187o a hospice for poorer pilgrims was erected. There was some metalliferous mining in the region in the 19th century, though this has become relatively unimportant.