Stone steps descend from an east-facing entrance to the water below. It is an unassuming structure, easy to pass without a second glance, yet for generations it was considered one of the more powerful sacred springs in the region, credited with curing ailments in both people and animals.

The well is dedicated to St Grellan, and its name, Tobergrellan, carries that dedication directly, "tobar" being the Irish word for well. A pattern, the traditional Irish gathering of prayer and community held at a holy site on a saint's feast day, took place here each year on the 29th of September. Ordnance Survey correspondence from the nineteenth century, later compiled and published by O'Flanagan in 1927, described it as having been "formerly looked upon as a most miraculous spring," which suggests that even then its wider following had already begun to fade. By 1960, when the Rev. Fr. Egan wrote about the well, attendance had contracted further. He noted that only a small number of devoted visitors continued to come, observing a set form of prayer, reciting prescribed Paters, Aves, and Glorias, drinking the water, and leaving a small object behind on departing. That last practice, Fr. Egan remarked, was almost certainly a survival of the much older custom of leaving a valued possession as a votive offering at a sacred site, the token made humble over time even as the impulse behind it persisted.