Yet this modest well at Mullaghcloe in County Westmeath draws people to it every year on the fifteenth of August, the feast of the Assumption, when a pilgrimage is made and mass is celebrated at the nearby altar. The well is known simply as the Sunday Well, a name old enough to appear on the Ordnance Survey six-inch map, placing it in that long tradition of Irish holy wells whose local significance outlasted any formal ecclesiastical endorsement.

The well sits roughly five metres to the north-east of the associated altar site, sheltered by a cluster of whitethorn trees and bushes. Whitethorn, or hawthorn, is a tree deeply associated in Irish folk tradition with sacred and liminal spaces, and its presence here fits a pattern seen at holy wells across the country. What the Sunday Well is said to offer is specific and unusual: the water is reputed to cure bad veins. This kind of precise therapeutic claim, attaching a particular ailment to a particular source, is characteristic of the older stratum of holy well belief in Ireland, where wells were understood to have distinct and localised powers rather than a general sanctifying virtue. At the time the site was recorded, there were no rags, medals, or other votive objects left around the well, which suggests either that the tradition of leaving such tokens has faded here or that the pilgrimage practice has become centred more on the mass than on individual acts of veneration.