That circle is a rath, the Irish term for a ringfort, the type of enclosed farmstead that once defined the rural landscape of early medieval Ireland. Thousands were built across the country, typically consisting of an earthen bank and ditch enclosing a family's dwelling and outbuildings. The Firmount example appeared on the 6-inch OS maps of 1842, 1904, and 1939, faithfully recorded across nearly a century of surveying. Then, at some point around 1979, it was levelled during field fence clearance.

That kind of loss was not unusual in the latter half of the twentieth century, when agricultural improvement schemes and land consolidation efforts removed a significant number of earthworks across Ireland, sometimes without any prior archaeological investigation. What makes the Firmount rath quietly affecting is precisely how long it endured before disappearing: nearly a millennium and a half of Irish history, give or take, reduced in a matter of days. The site had been pasture land, which likely contributed to its survival for as long as it did, since ploughing tends to be far more destructive to earthworks than grazing. Local information, rather than any formal excavation record, is the source for what happened to it.

Visitors to the area will find very little to see. The land remains in agricultural use, and only some faint undulations in the ground betray where the enclosing bank once stood. It is the kind of site that rewards patience and a calibrated eye, the slight softness in an otherwise level field, the almost imperceptible rise that means something if you know what you are looking for.