What makes it quietly remarkable is not its size but its shape: viewed from the north, the natural formation traces the outline of the letter P, a coincidence of geology that local people long ago read as something more than accidental.

The pool is known locally as Tobairín P, the diminutive Irish form suggesting something modest and familiar rather than grand. The P stands for Pádraig, Saint Patrick, and the association between the pool's letterform and the patron saint gave it the character of a holy well, a category of site found throughout Ireland where natural water sources became focal points for devotion, pilgrimage, and local religious custom. A small crucifix tucked into a crevice in the rock beside it marks the spot as one still regarded with some reverence. The detail was recorded by T. Robinson, the cartographer and writer whose meticulous documentation of Connemara and the Aran Islands brought many such quietly significant local features to wider attention.