The earthwork that sits on a low rise at the north-eastern end of an east-west ridge in County Sligo presents itself as a D-shape rather than the full circle you might expect, and that straight edge is telling. Where a modern field fence now runs along the north-west side, the enclosure simply stops, with no trace of any continuation beyond it. The most likely explanation is that roughly a third of what was once a complete circular enclosure has been levelled, probably through centuries of agricultural activity, leaving the surviving arc of bank and the fence line to define a space that measures approximately 24 metres north-east to south-west and 16 metres across to the fence.

A rath, to use the Irish term, is a ringfort, an enclosed farmstead of the early medieval period, typically dating from somewhere between the fifth and twelfth centuries. They were built in their thousands across Ireland, usually to shelter a family and their livestock, and they remain one of the most common archaeological monument types in the country. The bank at Ballygilcash is modest by any measure, constructed of earth and stone, standing only around 0.3 metres above the interior ground surface and just over half a metre on the outer face at the south-east. What makes the site quietly interesting is not its scale but its situation: a second rath lies approximately 95 metres to the west-north-west, meaning that two such enclosures once occupied the same ridge in close proximity. Paired or clustered ringforts are not unheard of in Ireland, and their relationship to one another, whether familial, sequential, or otherwise, is rarely easy to resolve from surface evidence alone.