Local tradition holds that St. Patrick himself founded this religious site, though the claim remains unverified. What is certain is that the monastery left its mark on the landscape; a magnetometer survey conducted by the Bernician Studies Group in 2014 revealed the ghostly outline of the original ecclesiastical enclosure surrounding the site, invisible to the naked eye but still detectable beneath the soil.

The heart of the site consists of a sub-rectangular graveyard containing several intriguing features from the monastery's early days. During a clean-up project in 2010, workers stumbled upon multiple cross-slabs that had gone unrecorded for centuries, adding new pieces to the historical puzzle. Among these discoveries, the Bernician Studies Group later identified a small, roughly-shaped freestanding cross, measuring just 40 centimetres high and 3 centimetres thick. This curious stone may represent an abandoned project; perhaps a medieval stonemason's practice piece or a cross that didn't quite meet specifications and was left unfinished.

The combination of archaeological survey work and chance discoveries continues to reveal Cooly's monastic past layer by layer. From the buried traces of its enclosure walls to the weathered cross-slabs scattered throughout the graveyard, each element tells part of the story of this Early Christian community that once thrived on the shores of Lough Foyle.