This subaqueous site, which only reveals itself when lake levels drop, consists of the substantial foundations of what was likely a fortified structure built on a small island or spit of land before the lake’s water level rose sometime after the mid-18th century. The remains form a square structure measuring approximately 21 metres on each side, constructed from coursed sandstone blocks, with some individual stones reaching an impressive 1.5 metres in length.

The southeastern and southwestern walls survive best, standing about a metre high beneath the water’s surface. These walls, roughly 2 metres thick, feature carefully laid sandstone blocks with a rubble core filling; a construction technique typical of medieval Irish fortifications. A regular gap measuring 2.85 metres wide along the southeastern side likely marks the original entrance, though it’s now largely blocked by collapsed masonry. The northeastern and northwestern walls have fared worse over the centuries, surviving only as scattered spreads of blocks and rubble across the lakebed.

What makes this site particularly intriguing is its context within Lough Currane, which contains several other submerged monuments, suggesting significant environmental changes to the area’s water levels over time. The historian Charles Smith noted the lake’s rising water level as early as 1756, which would have gradually submerged these structures. Today, the sandy lakebed around the castle foundations remains remarkably clear of large stones that might have tumbled from the structure, preserving the site’s footprint with unusual clarity. While no mortar or timber survives in the visible remains, the substantial nature of the construction and its strategic lakeside position suggest this was once an important defensive structure, possibly a tower house, guarding the southern shores of what is now one of Kerry’s most enigmatic archaeological landscapes.