Set in level grassland in County Galway, the site is a rath, a type of circular or subcircular earthen enclosure used throughout early medieval Ireland as a farmstead or defended homestead. This one measures roughly 34 metres east to west and 32 metres north to south, its boundary once defined by a raised bank and an external fosse, the ditch dug around the outside to create that bank from the spoil. Traces of what may have been a second, outer bank survive at the north-east, which would have made the enclosure more substantial in its original form.

The rath has not been well treated by time or land use. Quarrying has eaten into the enclosing bank at the west-south-west and across the stretch from north to east, and a field bank bisects the remaining earthworks at the south. An entrance causeway, the point where the fosse was left uncut to allow passage in and out, can still be made out on the western side. The name Lisnagree itself contains the Irish word lios, another term for this kind of enclosure, suggesting the site was significant enough to anchor the local place name, even as the physical remains diminished around it.