What makes Tobernavean stranger still is what sits outside that enclosure: three rectangular stone troughs, two positioned to the south and one to the northwest, their arrangement suggesting a deliberate, if now largely unreadable, logic.

The name itself offers a clue. Tobernavean derives from the Irish tobar na bhfian, most likely meaning the well of the Fianna, the legendary warrior band of Irish mythology, though place-name attributions of this kind were often applied long after any original meaning had blurred into folklore. Holy wells in Ireland occupy an unusual position in the landscape, frequently pre-Christian in origin yet absorbed into Catholic devotional practice over centuries. They were visited for healing, for patterns (the term used for a local pilgrimage or ritual circuit around a sacred site), and for the votive leaving of offerings. The stone troughs at Tobernavean may have served a practical function in managing the water flow from the spring, or they may have been integral to the ritual use of the site, holding water drawn from the well for specific purposes. No record clarifies which.