The one known locally as Lisheen, on the east bank of the Shannon in County Limerick, does the opposite. It backs directly onto the river, using the water itself as a defensive wall, and sits on low-lying pasture that floods in winter. That is not typical behaviour for a ringfort anywhere in Limerick, and it raises the question of whether this should be classified as a ringfort at all.

The site appears on the 1840 Ordnance Survey six-inch map under the name Lisheen, and by the time of the 1897 twenty-five-inch edition it is shown as a semi-circular enclosure of roughly 56 metres by 38 metres, its open side pressed against the Shannon. What survives today is somewhat reduced, measuring approximately 38 metres by 26 metres, enclosed by a wide bank with an external ditch that would have filled with water seasonally. A linear earthwork, some 60 metres long and 7 metres wide, extends southeast from the northeast end of the enclosure, with a ditch or fosse on either side of it, and there are hints of further earthworks along the riverbank to the northeast. A rectangular depression near the river on the northern side of this linear feature adds to the sense that the arrangement was more complex than a simple farmstead enclosure. Researcher Edmond O'Donovan, who compiled the site record in 2020, drew a comparison with the Anglo-Norman ringwork castle at Clonmacnoise, and noted the parallel with cliff-edge forts, where a natural feature, a cliff or, in this case, a river, substitutes for a constructed rampart. The interior, he suggested, may have been accessible by boat directly from the Shannon.

The site sits on partially reclaimed flat pasture and the field remains liable to flooding, so timing matters. A satellite image taken on 6 February 2018 shows the water-filled ditch clearly, and winter or early spring is likely when the defensive logic of the place becomes most legible on the ground. The earthworks are low and eroded, and without the context of the Shannon immediately beside them they could easily read as unremarkable field boundaries. Ordnance Survey Ireland mapping and the publicly available Google Earth orthoimagery are the most useful tools for orienting yourself before visiting, particularly for tracing the linear earthwork extending to the southeast.