The 1839 Ordnance Survey six-inch map labels the spot simply as 'Monastery', without pinning down an exact location. By the 1900 revision, the cartographers had grown more cautious, renaming it 'Monastery (Site of)' and planting a small cross to fix the point. That quiet editorial retreat, from confident label to hedged site-marker, captures rather well the uncertainty that surrounds the place.

The historical case for a monastery here rests largely on the historian William Carrigan, writing in 1905, who identified this as the location of the Abbey of Killenny, a daughter house of Jerpoint Abbey, the well-preserved Cistercian monastery a few miles to the south-west. Cistercian daughter houses were foundations sent out from an established abbey to colonise new sites, carrying with them the customs and personnel of the mother house. According to Carrigan, the abbey at Barrowmount was founded and endowed by Dermod O'Ryan, Chief of Idrone, and its first monks were sent from Jerpoint under Abbot Felix O'Dulany. A foundation charter places these events between 1162 and 1166. Adding a stranger layer to this account, a local tradition recorded in the 1839 Ordnance Survey Letters describes the monks abandoning the Barrowmount site after some form of witchcraft prevented them from building; whatever was raised during the day was said to be thrown down at night, forcing them to relocate to Graigue instead. The author of those same letters was sceptical that any monastery had stood here at all, and suggested that the structure in question was more likely a castle, later demolished to supply building material for Brookhill House nearby. By 1839, Brookhill House was itself already in ruins. A field inspection in 1994 found large granite blocks and cut-stone fragments incorporated into the surviving outbuildings and walls of the house site, pieces that appeared to come from a medieval building, though whether that building was ecclesiastical or secular could not be determined.