Records from that year show it was owned by one Jonick Ohalorane, though the castle itself may have been built earlier. By the time antiquarians began documenting Ireland’s ruins in the 19th century, the castle was already in an advanced state of decay. The Ordnance Survey Letters from the 1920s noted that only a small portion of ruins could still be seen, whilst Lord Killanin’s survey in 1947 found just foundation remnants.

What makes Oghery Castle particularly intriguing is the mystery surrounding its current state. The foundations that Killanin observed appear to belong not to the medieval castle, but to a much later single-storey building from the 18th or 19th century. This suggests that at some point, perhaps after the original castle fell into ruin, someone built a more modest structure on the same spot, possibly reusing stones from the earlier fortification.

Today, visitors to An Cnoc Bán would be hard pressed to find any visible trace of either structure on the surface. The island has reclaimed what was once a defensive stronghold, leaving only historical records and archaeological surveys to tell the story of this once-occupied site. The castle’s complete disappearance serves as a reminder of how quickly Ireland’s built heritage can vanish when left to the elements, particularly in the wet climate of County Galway’s lakelands.