This is a rath, the more specific term for an earthen ringfort, a type of enclosed farmstead built in early medieval Ireland, typically between the sixth and tenth centuries. Thousands of them survive across the country in varying states of preservation, though their individual quirks of construction and setting can differ considerably from one to the next.

The Gortnacreha Upper example measures 28 metres in diameter, enclosed by an earthen bank that rises roughly a metre on the interior and a little more, about 1.2 metres, on the exterior. Outside the bank runs a fosse, which is simply the ditch from which the bank material was originally dug; here it survives to a depth of 0.7 metres and a width of 1.8 metres. What makes this particular site slightly unusual is the way the topography works against a simple reading of the enclosure. The northern half of the interior is more or less level, but the southern half slopes downward toward the north, a consequence of the site being set into a steep gradient rather than on flat ground. Field boundaries that once abutted the enclosure at the east and north have since been removed, which means the immediate landscape around the rath has been altered from what it would have looked like even in the recent past. The site was compiled by Denis Power and recorded on the national monuments database.

The rath sits in pasture with some scrub cover taking hold inside the enclosure, so the interior can feel a little rougher underfoot than the surrounding fields. Because of the north-facing aspect and the steepness of the slope, the site can be shadier and damper than you might expect, even in summer. The bank and fosse are clearest when viewed from the downhill, northern side, where the external height of the bank is most pronounced. As with most ringforts in agricultural land, access depends entirely on the landowner, and there is no formal public access or signage. Visiting requires some prior research into exactly which field the monument occupies, and the usual courtesies of asking permission before crossing private land.