According to folklore collected from Killaghteen National School, St Patrick once passed through Ardagh and asked at a house for a drink of water. The people refused him, and he cursed a well so that anyone who drank from it would die. Regretting his anger, he partially lifted the curse, but only partially: the revised version held that birds, rather than people, would be the ones to die from its water. It is the kind of local story that lodges in the mind, partly because of how it quietly transfers guilt from saint to community and back again.

The well is dedicated to St Molua, and it sits roughly 135 metres south of Ardagh's main street, with the ruins of a medieval church and graveyard lying about 65 metres to the north-northeast. A 1906 account by Begley described the well as it was then understood: once shaded by an old ash tree with a girth of four feet and six inches at the base, which had by that point already disappeared. Parishioners were still visiting on the 3rd of August, the eve of St Molua's feast day, to pay rounds, a traditional practice at holy wells involving a set number of prayers said while walking a prescribed circuit around the site. Around fifty years before Begley was writing, the 4th of August had been observed as a full parish holiday in the saint's honour, though that custom had faded by 1906. Photographs taken by Caoimhín Ó Danachair in 1954, now held in the National Folklore Collection at UCD, show the site as it appeared in the mid-twentieth century.

The well lies on marshy ground, so the approach can be soft underfoot, particularly after rain. It is located south of the graveyard associated with the medieval church ruins, which provides a useful landmark when orienting yourself from the village. The 3rd of August remains the traditional occasion for visiting, carrying on the pattern that Begley documented over a century ago, and that date gives the site a context that a quiet weekday visit on its own cannot quite replicate.