What the 1897 Ordnance Survey map marks as a holy well at Derryrush in County Kerry turns out, on investigation, to be a lake, and even that is largely gone now, drained away into a level marshy depression in the undulating pasture. What remains is essentially an absence, yet people still come to it every year to perform the old rituals.

The site sits roughly forty metres south-east of what was once Lough Mackeenlaun. Local tradition, recorded by O'Brien in 1970, is unambiguous on the matter: the lake was the well. Pilgrims came in considerable numbers through the nineteenth and early twentieth centuries to take water directly from it, treating the lough itself as the sacred source rather than any stone-lined shaft or spring. The distinction between lake and well appears to have been immaterial to those who made the journey. The site does not stand alone in the landscape; immediately to the east lie two cross-inscribed stones and the remains of a hermitage, suggesting a cluster of early Christian activity that would have given the place its sanctity long before the pilgrimage tradition was formalised.

The practice of "rounds", the ritual circumambulation of a sacred site that is a common feature of Irish pilgrimage tradition, was evidently in decline at some point but has been revived in recent years. These take place annually on the 7th and 8th of July. Visitors approaching the site should expect wet ground; the former lakebed is marshy underfoot, and the landscape gives little away about the centuries of devotion it once drew.