The fourth owner was listed as Joan Ny Conroy, though despite the prominence of these landowners, no castle appears in the historical records from that period. This absence is particularly intriguing given the status typically associated with such substantial land ownership in medieval and early modern Ireland.

The mystery deepens when examining later cartographic evidence. The 1911 edition of the Ordnance Survey six-inch map depicts what it calls ‘Ballyellia Castle’ as a hollow rectangular structure, roughly 20 metres square, situated within the northeastern section of a larger enclosure. The map represents it with gothic lettering, suggesting the cartographers believed it to be a site of some antiquity, yet today nothing remains visible at ground level where this structure supposedly stood.

Whether Ballyellia Castle was a genuine medieval fortification that had already vanished by the time of the 1641 records, or perhaps a later misidentification by Ordnance Survey cartographers, remains unclear. The site, catalogued as RO017-143001 in archaeological records, continues to puzzle historians; its phantom presence on a single map edition serving as the only tangible evidence that a castle may have once commanded this corner of County Roscommon.