St Michael’s Well is the sacred well of the Caerwys Church, also dedicated to St Michael. It was described in 1912 as ” A natural basin of limestone, about 12 feet across east to west, and 20 feet north and south, in which the water collects from the springs above, the spring within the basin adding its quota; the water discharges over its southern lip forming a little brook which Lhuyd calls Avon NEhangel, St Michael’s stream.” 
Jones records that needles were once offered at the well for the cure of warts and sore eyes. Samuel Lewis writes that “the spring was much resorted to by the credulous on the morning of Easter day for the purpose of drinking it.”
We visited in June 2011. The site lies in a deep ravine, which requires a scramble down from the pathway running through Maesmynan wood. We found a considerable number of tree branches in the well and larger branches and old tree trunks lying up against the back wall of the well from which much of the water was supposed to flow, making it initially quite difficult to determine the precise sources of the water entering the well. Water does seem to enter from under the rock wall at the back of the well.
The depth of the water appeared to be no more than about 6 inches, although the bowl is full of weed and wood debris. The well basin is surrounded by stone cliffs, and with the overhanging trees ths location is particulary gloomy. There was a quantity of loose stones lying around which may suggest the remains of building at the site in the past, although whether there has been a chapel at the site is a matter of conjecture. 
Some reports refer to a cave or niche above the well in which at some time in the past an image of St Michael has been placed. There is a small niche in the rock wall to the left of the well, and if you scramble up to the next level there is a larger cave, illustrated above.
 An Inventory of the Ancient Monuments in Wales and Monmouthshire. Vol 2 – Flintshire. Royal Commission on Ancient and Historical Monuments. 1912.
 Witchcraft in Seventeenth-Century Flintshire (PART ONE) by J. Gwynn Wiliams, M.A. Journal of the Flintshire Historical Society, 1973-1974, 26, p. 16-33