This one is remarkable for what does not. In Carrowndangan townland in County Mayo, there is believed to have been a chapel, though no stone, no outline, and no earthwork remains to mark where it stood. The only evidence for its existence is a single reference in a 1904 publication, and even that stops short of certainty, describing it only as a possible chapel.

The reference comes from Knox, writing in 1904, who noted the site within Ballinamore Demesne. The chapel may have formed part of a small cluster of related features, potentially associated with a rath and a holy well in the same area. A rath is an early medieval enclosed settlement, typically defined by an earthen bank and ditch, and the grouping of a rath, a holy well, and a place of worship in close proximity is a pattern found in various parts of Ireland, suggesting a locality that held some spiritual or communal significance over a long period. Whether that was the case here, however, remains unclear. The association is speculative, the chapel itself is unconfirmed, and the landscape has since absorbed whatever physical traces there may once have been.