Tobar Lachtín, on the hill of Knocknagranshy in County Limerick, carries exactly that reputation. According to local folklore recorded from Ballymartin National School, a woman once brought her washing to the well and used its waters to launder clothing, an act considered a profanation. The following morning, the spring had shifted from one side of the overhanging ash tree to the other. The well, the story goes, simply refused to stay where it had been disrespected.

The site is dedicated to St. Lachtin, one of three saints of that name associated with the 6th or 7th century, whose name also appears near Newcastle in the place name Cill Lachtín. The well appears on the Ordnance Survey map of 1840 as Tober Laghteen, and it retains a small masonry cupola, a domed stone canopy of the kind built to shelter and dignify a sacred spring, bearing a carved inscription: "This was erected by James Keating in ye year of our Lord 1791 that lived in Grangehill. Pray for him." The well's waters were traditionally believed to cure eye ailments, and the pattern day, the annual gathering of devotions and rounds performed by walking circuits of the well in prayer, fell on the 19th of March, the feast of the saint. That practice continued until roughly forty years before the Schools' Collection recorded it in the mid-twentieth century. Rags were hung on the ash tree as offerings, a custom widespread at Irish holy wells, where cloth left at the site was thought to transfer illness or carry a petition.

The well is situated in Grangehill, about half a mile south of Tory Hill, and lies within a quarter of a mile of a vault-like structure known as Teampuilín na Webbana, which sits on the summit of the hill and is said to contain human bones. The folklorist Caoimhín Ó Danachair photographed the site in 1954; those images, held by the National Folklore Collection at UCD, show the cupola and the great ash still in place. By the time of his visit, the cupola itself had run dry, though the spring continued to emerge beside it in a pool roughly three yards across, still serving a practical purpose for domestic use and cattle.