The enclosure measures roughly 75 metres north to south and 68 metres east to west, defined by a scarped edge, a fosse, and an outer bank. A fosse, in this context, is simply a defensive or boundary ditch dug around an enclosure, with the spoil typically thrown outward to form a bank beyond it. At its best-preserved western arc, the internal face of the bank still stands around 2.9 metres high, giving a reasonable impression of what the whole circuit once looked like, though along the northeast and southwest the scarp has softened, the fosse has largely silted up, and the bank has been reduced to little more than a grassy swell.

What makes the site slightly unusual is what has happened inside it since it fell out of use. The interior was never artificially levelled; it simply follows the natural contours of the ridge, so that the northern and southern flanks sit roughly 2.5 metres above the surrounding ground, while the centre and the eastern and western ends are flush with the fields outside. Two quarry pits have been cut into the earthwork at the north, one rectangular and sizeable at around 20 by 10 metres, the other a smaller oval; both bite into the scarp and compromise its integrity. A causeway crossing the fosse at the northwest appears to be a modern addition, probably created to give access to those same quarry workings, which are now disused. A drystone field wall, running roughly north-northeast to south-southwest, has been built straight through the enclosure's interior at some later point. None of these later interventions are unusual in themselves; across Ireland, prehistoric and early medieval earthworks have been quarried, ploughed, subdivided, and quietly absorbed into the working agricultural landscape for generations. What survives here survives largely by accident.

The enclosure does not stand alone. Two further earthworks, one a rath and one another enclosure, lie about 90 metres to the northwest, and a second rath sits roughly 160 metres to the north. A rath is a ringfort, typically a circular enclosure defined by an earthen bank and ditch, associated broadly with early medieval settlement in Ireland. The clustering of these monuments on adjacent ground raises questions about how this part of Sligo was organised and used, though without excavation those questions remain open. The hilltop position, offering long views in every direction, suggests that whoever built the enclosure at Carrowgilhooly understood the value of the ground they chose.