Yet the earthwork beneath carries nearly a thousand years of layered occupation, and the scarp that drops some six metres along its southeastern edge, where the river bends past, suggests something far more deliberate than a natural rise in the ground.

The enclosure is thought to be broadly contemporary with a thirteenth-century castle that survives in its northwestern corner, but it may have absorbed something much older. Early sources associate the site with Dún Mór, a fortification attributed to Turlough O'Connor, the powerful Connacht king, in the early twelfth century. The name itself, meaning great fort, points to a place of some regional significance. When the local antiquarian Neary surveyed the site in the early twentieth century, the physical evidence was considerably more legible than it is today. He recorded the line of ruined perimeter walls, one stretch of which still stood to a height of almost five metres along the southern side. He also noted a small square building projecting through that wall, and beside it a sunken walled recess, roughly a metre wide, one and a half metres long, and nearly two metres deep, which he speculated may have functioned as a latrine, a not uncommon arrangement in medieval fortifications. A gate and a ditch to the west were noted separately by Knox, writing in 1911 and again in 1921. To the west of the main rectangular platform, at a slightly lower level and now cut off from it by a north-south laneway, a roughly oval secondary enclosure of around forty metres across once served as a courtyard. Neary found a small remnant of its wall still standing in what he called Commin's garden.

Almost none of these features are visible on the surface today. What remains is the platform itself, gently sloping from north to south, scattered with earthen mounds, and edged by the two limekilns, a kiln being a structure used to burn limestone into quicklime for agricultural or building use, that were inserted into the margins of the earthwork at some later point. The site sits quietly in a landscape that has moved on around it, the medieval layers pressed down beneath ordinary agricultural ground.