This ancient mound, situated about a quarter of a mile northeast of the town, bore a striking resemblance to the Castleguard Motte at Dawson’s Demesne. When the antiquarian Tempest documented the site in 1952, he noted with some regret that the mound had been levelled approximately a century earlier, leaving only traces of what must have been an impressive defensive structure.

The Ordnance Survey Letters from the 19th century provide one of the few surviving descriptions of the site, referring to it as a small fort. The name “Liss” itself offers a clue to its origins; derived from the Irish word “lios”, it typically denotes a ringfort or enclosed farmstead that would have been occupied during the early medieval period. These circular earthwork enclosures, often topped with wooden palisades, were the most common form of settlement in rural Ireland between roughly 500 and 1200 AD.

Today, visitors to Riverstown will find little visible evidence of this once-prominent landmark. The site’s destruction in the mid-19th century represents a common fate for many of Ireland’s archaeological monuments during that era, when agricultural improvements and urban expansion often took precedence over heritage preservation. What remains is primarily documentary evidence; the descriptions preserved in the Archaeological Inventory of County Louth and the Archaeological Survey, published in 1986 and 1991 respectively, which continue to be updated as new research emerges.