Holywell gained it name from St Winifride's Well which has attracted pilgrims since the seventh century.
The shrine to St Winifride gained a reputation as the 'Lourdes of Wales' providing water (believed to have healing properties) for visitors. The site where St Winifride was beheaded consists of a chapel and well and is known as one of the seven wonders of Wales.
The town has always been an important gateway into Wales and Basingwerk Abbey was founded nearby in 1132. The monks were the first to harness the available water power to grind corn and treat the wool from their flocks of sheep. This abundance of water, together with mineral resources, meant that Holywell became a leading centre for milling and mining. Examples of local industries included the Battery Works which produced brass pots and pans, Meadow Mill specialised in rolling copper sheets, Abbey Wire Mill made copper and brass wire and there was also a cotton mill and nearby lead mines. This centre for industry is now the Greenfield Valley Heritage Park which gives an idea of the working and living conditions for people in the area. The population of Holywell (Treffynnon in Welsh) at the last census was 7,531.