Today, visitors will find only a linear grass-covered bank stretching about 11 metres from east to west, possibly the last trace of what historical maps from 1842, 1905 and 1936 show as an enclosing wall. The exact location of Shanagh Castle has been a source of confusion for centuries, with various documentary sources placing it in different spots around the area.

The Down Survey maps of 1655-6 add to this mystery by appearing to swap the positions of Clogher and Shanagh townlands compared to later Ordnance Survey maps. These earlier surveys show the castle in what they label as the northeast corner of Clogher townland, though this area is now known as Shanagh. Meanwhile, the Ordnance Survey six-inch maps position the castle site approximately 130 metres southwest of Clogher Hill, whilst local historian Healy suggested in 1988 that the castle actually sat atop Clogher Hill itself.

What we do know for certain is that this was once the stronghold of the Nagle family, an old Cork dynasty who lost the property during the Cromwellian confiscations. In 1657, the castle and its lands were granted to Hughes as part of the massive redistribution of Irish estates that followed the Confederate Wars. Though the stones have long since vanished, likely repurposed for nearby buildings and field walls, the site remains a tangible link to the turbulent period when ancient Gaelic and Old English families saw their ancestral homes pass into new hands.