Holywell is a market town and community in Flintshire, Wales. It lies to the west of the estuary of the River Dee. The community includes Greenf…Holywell is a market town and community in Flintshire, Wales. It lies to the west of the estuary of the River Dee. The community includes Greenfield. In 2011 it had a population of 8,886. The name Holywell is literally holy + well in reference to St Winefride's Well, which is situated in the town. Similarly, its Welsh name, Treffynnon, is a compound of tre "town" + ffynnon "well", meaning "town of well".