This unusual monument consists of a heather-covered drystone wall, approximately 35 metres in diameter and standing 0.7 metres high, enclosing a waterlogged interior. At its centre sits a low, flat-topped rectangular cairn, known locally as a leacht, which local tradition claims marks the burial site of warriors who fell in an ancient battle.

What makes this site particularly intriguing is its soggy, sphagnum-rich interior; a characteristic quite unusual for monuments of this type. The ground gives way considerably underfoot, suggesting the original surface level was much lower than what visitors encounter today. Archaeological evidence points to the presence of an inner bank of earth and stone visible along the eastern section, though this secondary enclosure doesn’t completely circle the interior. It’s possible that the site’s waterlogged state is a relatively recent development, caused by blocked field drains that once carried water away from the mountain slopes above.

From the higher ground to the east, the monument’s amphitheatre-like setting becomes apparent, and its combination of features; the central cairn, the potentially concave interior, and the double enclosing elements; has led some researchers to suggest it might be a pond barrow, a rare type of Bronze Age burial monument. However, its true purpose remains uncertain, and it may represent an unknown form of ritual monument unique to this region. Whatever its original function, Caiseal Charna stands as a testament to the complex ritual landscape of ancient Ireland, its waterlogged interior preserving mysteries that continue to intrigue both scholars and locals alike.