It measures roughly two metres in length and looks, at first glance, like nothing more than a depression worn into the coastal rock. But locally it is known as Tobar Cholmcille, a holy well dedicated to Saint Colmcille, one of the most widely venerated figures in the early Irish church, and people still come to it.

Holy wells in Ireland occupy a peculiar space between the ancient and the everyday. They were often sites of pre-Christian water veneration that later became associated with Christian saints, and they remain places of quiet, persistent devotion in many communities. What makes Tobar Cholmcille on Maínis quietly striking is its setting: not a stone-lined well in a sheltered field with votive offerings tied to a nearby bush, but a coastal rockpool, subject to tides and salt air, right at the margin of the land. The absence of offerings noted at the site does not suggest neglect; it appears to attract more regular local use than at least one other recorded holy well in the area, according to information gathered from Tim Robinson, the cartographer and writer whose meticulous mapping of Connemara and the Aran Islands documented precisely this kind of local knowledge. Just to the south of the well, a vein of white quartz runs through an adjacent rockpool. Quartz has its own long resonance in Irish sacred landscapes, frequently found at passage tombs and burial sites, and its presence here, whether coincidental or not, adds a particular quality to the spot.