What survives at the site, how old it is, who built it, and what it may once have served, all of that remains undocumented in any publicly accessible form. The site is formally recognised, catalogued by classification, but the details that would place it in its landscape and its century have not yet been made available. That gap is itself a kind of curiosity: a place that officially exists but remains, for now, without a story attached to it.

Church sites in rural Cork townlands can range from early medieval foundations associated with local saints or monastic traditions, through to post-Norman parish churches built in the twelfth or thirteenth centuries, to later structures that fell out of use after the upheavals of the sixteenth and seventeenth centuries. Without specific documentation for this site, it is not possible to say which tradition Grillagh belongs to. The placename itself may offer some clue in time; Grillagh derives from the Irish, and many such names preserve traces of landscape features or early settlement patterns, though drawing conclusions without corroborating evidence would be speculative. For now, the site belongs to that large and not uncommon category of Irish ecclesiastical remains whose physical presence outlasts the written record that might explain them.