Tobar Rí an Domhnaigh, the Well of the King of Sunday, sits on a north-facing slope in a pasture field near the north-east boundary of the Boolasallagh townland. It is a modest thing physically, a water-filled depression roughly 1.8 metres long, a metre wide, and 0.6 metres deep, with stones scattered around it and, when visited around the turn of this century, a statue of Our Lady resting beneath a young tree on its south-east side. Holy wells in Ireland are among the older continuities in the landscape, sites where pre-Christian veneration of water sources was gradually absorbed into Christian practice, usually attached to a saint's feast day or associated with particular curative powers. This one earned its reputation through a domestic test rather than a miracle: a local woman drew water from the depression, brought it home, and found it simply would not come to the boil.

That founding story was recorded through Michael Culloty of Toornanoulagh, and it anchors a whole cluster of legends that gathered around the well over time. People came to pray, to seek cures, and to leave offerings of statues, medals, and glass ornaments. Silver coins thrown into the water were believed by some to yield the best results, a belief that created obvious opportunities for exploitation. Culloty recalled the tale of a publican from Firies village who, on her way to the well one day, pocketed a damaged half-crown from her till as her offering. Returning shortly afterwards, she found the same coin back in the till, and noticed a local man who lived near the well standing at her counter working through a pint. On all subsequent visits, she is said to have left her money where it was, stating plainly that she had no intention of being paid for drink with her own money. The well was also associated with more solemn warnings: a youth who removed rosary beads from it reportedly woke that same night with a badly swollen leg, the beads having emerged from within it. Rounds, the traditional devotional circuits made around such sites while reciting prayers, were performed here in the past, though by the early 2000s that custom had died out entirely.