A ringfort, or rath, once occupied a carefully chosen position on level ground at the foot of a north-facing slope, perched above a natural bluff that drops steeply to a stream below. Ringforts are the most common field monument in Ireland, roughly circular enclosures defined by earthen banks and ditches, built during the early medieval period as farmsteads for individual farming families. This one measured approximately forty metres in diameter, a fairly typical size, and its location above a natural defensive feature suggests whoever chose the spot knew what they were doing. Today, the pasture gives no hint of any of this.

The fort was still visible, at least on paper, when the Ordnance Survey produced its six-inch map in 1842, which recorded the enclosure as a roughly circular feature in the landscape. At some point after that survey, the earthworks were levelled, most likely through agricultural improvement, and the site was absorbed into the surrounding farmland. This kind of loss is not unusual. Tens of thousands of ringforts once dotted the Irish countryside, and a significant proportion have been destroyed since the nineteenth century, ploughed out or cleared to make way for more productive land use. What remains at Glentrasna is essentially a location, a set of coordinates where something once stood.