This rectangular earthwork, measuring approximately 50 metres north to south and 40 metres east to west, represents one of the better examples of Anglo-Norman defensive settlements that once dotted the Irish countryside. The site takes its name, meaning ‘Fort of the Water’, from the substantial waterlogged fosse that still surrounds the entire structure, a defensive moat that would have provided both protection and a clear statement of authority in the medieval landscape.

The earthen banks that define this enclosure remain impressively intact, particularly on the southern side where they rise to 2.65 metres externally, with the interior height reaching 2.2 metres. The western and northern banks, whilst less imposing, still create a formidable barrier, and the eastern side features a scarp dropping about a metre to the fosse below. What makes this site particularly interesting is the presence of a berm, a flat ledge between the fosse and the external face of the bank on both the southern and northern sides, measuring 2 metres wide. The banks reach their greatest height at all four corners, a defensive feature that would have provided optimal vantage points for surveillance. A causewayed entrance, 2.5 metres wide, breaks the western bank at its southern end, marking the original access point to this fortified enclosure.

Today, the interior remains waterlogged and densely overgrown, making detailed investigation challenging, but the site’s preservation offers valuable insights into medieval settlement patterns in North Cork. First documented by Barry in 1981, Lios an Uisce forms part of a broader defensive landscape; another moated site lies just 500 metres to the northwest, suggesting this area held particular strategic or economic importance during the medieval period. The respect shown by later townland boundaries to the southern bank of the enclosure indicates that this earthwork has long been recognised as a significant landscape feature, its presence shaping the agricultural patterns that developed around it over subsequent centuries.