A drumlin, for those unfamiliar with the Irish midland landscape, is a smooth, elongated hill shaped by glacial deposits, and their slopes were favoured spots for the earthwork enclosures known as raths or ringforts. This particular example at Lyonstown measures somewhere between 45 and 50 metres in diameter, its perimeter marked by an earthen bank now smothered in vegetation. Internal facing stones are still visible within that bank, suggesting a degree of construction more deliberate than a simple heaped mound, and faint traces of an outer fosse, a defensive ditch, survive around the exterior.

Ringforts are among the most common archaeological monument types in Ireland, with tens of thousands recorded across the country, most of them dating to the early medieval period, roughly the fifth to the twelfth century. They functioned primarily as enclosed farmsteads, the bank and ditch defining a household's space rather than forming a serious military defence. What makes this example quietly notable is less any single dramatic feature than the combination of modest but legible details: the variation in the bank's external height, running from 0.4 metres to as much as 1.8 metres in places, the remnant fosse some three to three and a half metres wide, and the internal stonework peeking through the overgrowth. There is no identifiable entrance surviving, which is not unusual given how much these sites have been altered by centuries of agricultural activity and vegetation growth.