It is a rath, the most common type of monument in the Irish landscape, a roughly circular enclosure built from an earthen bank and an outer ditch, known as a fosse, that once defined a farmstead or settlement during the early medieval period. This particular example measures around fifty metres across on its east-west axis, though only the northern stretch of its bank survives in recognisable form. Elsewhere, the enclosing element has reduced to a scarp, a simple slope in the ground where the earthwork has eroded or been gradually absorbed into the surrounding terrain.

A field bank cuts across the monument at both its south-east and south-west, a detail that quietly tells a longer story of how the Irish countryside was reorganised for farming in the post-medieval centuries, often at the expense of older features underfoot. The rath at Mountkelly was recorded by Knight around 1975 and later included in the published Archaeological Inventory of County Galway, Volume II, covering North Galway. That inventory, compiled by Olive Alcock, Kathy de hÓra, and Paul Gosling, appeared in 1999 and remains a foundational reference for the archaeology of the region. The classification of this site as poorly preserved is honest rather than dismissive; it reflects how thoroughly later land use has overlaid an enclosure that, in its original form, would have presented a substantial and deliberate presence on the hillside.