The well at Killonahan, in County Limerick, is not one of them. What marks it out is precisely its absence, a site defined less by what it is than by what it has ceased to be, a place where devotion quietly ran dry and memory did not long outlast it.

The well was dedicated to St Sennan, and it appears on the Ordnance Survey map of 1840, identified by name. Holy wells, which are natural springs or water sources associated with a particular saint, were historically sites of pattern days, localised festivals combining religious observance with communal gathering. By the time the folklorist Caoimhín Ó Danachair came to record it in 1955, drawing on earlier Ordnance Survey Letters, the picture was already one of slow erasure. The well had dried up. Local people had frequented it as a holy well about twenty years prior to Ó Danachair's writing, meaning sometime in the 1930s, but by the mid-twentieth century even the oral tradition had lapsed. His note is brief and a little melancholy in its terseness: 'No tradition survives.'

The 1840 map marks the location, so a determined visitor with access to historical Ordnance Survey records could attempt to identify the spot near Killonahan. What they would find is uncertain, given that the well had already dried up before the 1950s and no physical description of the site survives in the available record. The value of a visit, if one were to make it, lies less in any visible feature than in the exercise of imagining what once gathered people here, the saint's name, the water, the occasion, now all equally gone.