In Knockainy West, County Limerick, there is a holy well that fits this description almost perfectly. St. Mary's Well appears on the Ordnance Survey map, marked with the quiet authority of a feature that was once well known, yet by the mid-twentieth century it had effectively ceased to exist in any meaningful physical sense. No stonework, no basin, no votive offerings. Nothing remains at the surface.

Holy wells were a fixture of Irish religious and social life for centuries, typically serving as sites of pattern days, rounds, and local devotion, often dedicated to a saint whose feast day structured the annual gathering. This particular well stood just outside the wall of the old Catholic church at Knockainy West. By 1944, when O'Kelly recorded the site, it had already been closed in and all acts of devotion had stopped. A decade later, writing in 1955, Ó Danachair noted something more final still: that the well had disappeared entirely, and that its former existence was known to very few people in the district. The Bradley survey of 1989 placed it in the field to the south of the church, which at least offers a rough geographical anchor, though it confirms nothing about what, if anything, a visitor might see there today.

For anyone wishing to look, the site lies in agricultural land near the old church at Knockainy West, and access to the relevant field would require landowner permission. There is no feature to find, which is in its own way the point. The Ordnance Survey name endures; the physical reality does not. What makes this place worth noting is precisely that gap between cartographic memory and the ground itself, a well that outlasted its water, its stones, and eventually almost all local knowledge of it.