The moated site at Lisnanarriagh appears on historical Ordnance Survey maps from 1837 and 1914 as a circular embanked enclosure, roughly 50 metres across. Today, what remains is a nearly circular area measuring about 40 metres east to west and 36 metres north to south, surrounded by a water-filled moat that varies in width from 4 to 8 metres.

The monument has seen better days; a laneway now cuts right through it from northeast to southwest, connecting the main road to some houses on the western side. The moat itself has been filled in along the southwestern section, and someone has dug a 6-metre-wide channel from the northwestern perimeter extending about 15 metres toward the centre, though its purpose remains unclear. The southern half of the enclosure is covered in grass, whilst the northern portion has become overgrown with vegetation and mature trees.

Despite archaeological testing conducted in 2004 just 20 metres southeast of the site, no artefacts or materials were discovered that could shed light on its origins or use. These moated sites, found throughout Ireland, were typically built by Anglo-Norman settlers in the 13th and 14th centuries as fortified farmsteads or minor defensive positions. The water-filled moat would have served both as a defensive barrier and possibly for drainage on this low-lying floodplain near the shores of Lough Ree.