First recorded on the 1840 Ordnance Survey map, this medieval earthwork appears as a roughly rectangular enclosure with a distinctively rounded western end. While much of the original structure has been lost to time, a significant portion of its defensive earthworks remains visible in the landscape today.

The surviving section consists of a semicircular arc of earth and stone banking that curves from west through north to northeast, now serving as a field boundary for local farmers. This remnant measures about 2.5 metres wide and stands roughly one metre high; a modest but telling fragment of what would once have been a complete defensive circuit. Such moated sites were typically built between the 13th and 14th centuries, often by Anglo-Norman settlers or prosperous Irish families seeking to protect their homesteads and demonstrate their social status.

These earthwork enclosures served multiple purposes beyond defence. The raised banks and water-filled ditches helped drain the land, kept livestock contained, and marked out the boundaries of the farmstead. The rectangular shape with its rounded end at Pallas Upper follows a common pattern found throughout Ireland, suggesting this was once home to a substantial dwelling, perhaps timber-framed, along with associated farm buildings and storage structures within the protected space.