It surrounds a natural spring, and for generations people came to it not for drinking water but for their eyes. The well is correctly known as Tobar Éinne, the well of Enda, though the anglicised form Tobereany is what most maps and records carry.

Holy wells dedicated to early Irish saints were frequently credited with curative properties, often very specific ones: a well might be sought out for joint pain, or skin complaints, or indeed failing sight. This one's association with eye diseases was noted by Lord Killanin in 1947 and repeated in the guide to Irish antiquities he co-authored with Michael Duignan in 1967. The well lies some 85 metres to the northwest of, and upslope from, a small oratory, the kind of simple early Christian prayer cell that punctuates the religious landscape of the west of Ireland. The proximity of well and oratory is no accident; across Ireland, sacred springs were commonly drawn into the orbit of early ecclesiastical sites, their pre-Christian significance absorbed and reframed within a Christian context. The drystone enclosure here, an oval structure measuring 1.17 metres by 0.8 metres and open at the southeast, is a modest piece of work, functional rather than ornate, built to define and protect the source rather than to impress.