Though the castle itself has long since vanished, demolished in the past to provide building materials for nearby farmhouses, the earthwork platform that once supported it remains visible. This rectangular platform, measuring roughly 30 by 32 metres internally, is defined by a low bank and an outer defensive ditch on three sides. The northern side preserves these features best, with the bank rising half a metre high and the U-shaped ditch averaging seven metres wide and over a metre deep. A causeway interrupting the eastern ditch likely marks where the original entrance stood, possibly once featuring a bridge over the channelled stream that still flows alongside.

The castle belonged to the MacCrohan branch of the O’Sullivan Mores, appearing in old manuscripts as ‘Letirmiccrohan’. Historical records show it was occupied by one Cnogher MacCroghon in 1656, but following the Cromwellian conquest, the property was confiscated and granted to Alexander Eagers in 1667. By 1841, no trace of the actual castle structure survived according to the Ordnance Survey Letters, and local historian Delap confirmed in 1910 that the stone had been repurposed for construction projects.

Today, visitors to the site will find an uneven interior space raised slightly above the surrounding ground level. In the northwest quadrant, a shallow hollow surrounded by a low bank may indicate ancillary structures, whilst a substantial sod-covered mound in the southeast quadrant, standing 1.4 metres high with a flat top measuring 8 by 7.2 metres, likely marks the castle’s original footprint. Though Mac Crehin’s Castle itself has disappeared into history and neighbouring farm buildings, these earthworks offer a tangible connection to the medieval landscape of Kerry and the complex political changes that swept through Ireland in the 17th century.