The well, known as Tobergrellaun, is dedicated to St. Grellan, and what remains of it is modest: an unroofed, roughly rectangular chamber of drystone construction, measuring about 1.65 metres along its longer axis, with an entrance facing west. The spring that once fed it has long since dried up, and the structure is poorly preserved, half absorbed into the field boundary that runs beside it. It is the kind of site that could be walked past without a second glance.

St. Grellan was a figure associated with the Uí Maine, the ancient kingdom that once dominated much of what is now south Roscommon and east Galway, and he is credited in early sources as their patron saint. Holy wells dedicated to local saints were common features of the Irish landscape, serving as focal points for communal prayer, pilgrimage, and the kind of informal medicine that blended Christian observance with much older beliefs about sacred water. According to a tradition recorded by O'Flanagan in 1927, the water from this particular well was held to be a general cure for all ailments, which places it firmly within that broad category of curative wells once found across every county in Ireland. The well chamber is built directly into the townland boundary wall, suggesting it was considered significant enough to be incorporated into the permanent marking of the land rather than left as a freestanding feature.