What lies beneath it is a holy well, a type of site found across Ireland where natural springs or water sources accumulated centuries of devotional significance, often associated with healing particular ailments. This one, Tobermacrehy, was once considered powerful enough to draw people seeking cures for diseases of the eyes, among other complaints. By 1839, however, a man named Curry found it dry and deserted, noting it was "now neglected and unfrequented, though formerly in great repute."

The well takes its name, and its history, from the medieval church of Kilmacreehy, which stands roughly 460 metres to the east. The connection between holy wells and nearby ecclesiastical sites is common in Ireland; wells were often associated with the same saint credited with founding a local church, and Kilmacreehy preserves the name of its patron in both places. Tobermacrehy appears by name on Ordnance Survey maps from 1840 and again on the 1916 revision, suggesting that even as the site fell out of active use, its identity remained legible on the landscape. The well shaft itself is lined with drystone masonry and covered now by a single flagstone, a modest structure that gives little outward sign of the reputation it once carried. The bay stretches out to the south, and higher ground rises to the north, leaving the well in its low, damp hollow much as it would have been when pilgrims last came looking for relief.