The site at Rahally came to light only because road construction requires archaeological investigation in advance, and what excavators found was not the kind of place that announces itself. About forty metres across and defined by a fosse, a term for a ditch used in early medieval earthwork construction, the enclosure had no dramatic monuments above ground, no visible walls. It had simply been there, quietly filling in, since the early medieval period.

The fosse was three metres wide and 1.2 metres deep, with traces of a low earth bank along its inner edge and what was probably an entrance gap on the southern side. Charcoal recovered from the fill dated the site's use to somewhere between AD 1020 and 1180. Among the objects found in the ditch were a penannular brooch, a type of open-ringed fastener common in early medieval Ireland, a yellow glass bead, an iron knife blade, and fragments of worked bone including pieces from combs. The food waste was perhaps the most informative find of all: grain, and bones from cattle, sheep, pig, horse, deer, dog, and wild goose, a picture of a community drawing on both domesticated animals and the wider landscape. The enclosure is thought to have functioned as an annex to the bivallate ringfort, a double-ditched defended farmstead, that sits immediately to its south-west. Two burials of children were also uncovered. A child of around twelve years was found in the fosse, dated to AD 1020 to 1200, and a younger child, aged between four and six, was found near the centre of the enclosure, with remains dating to AD 990 to 1160. The interpretation offered by the excavation report is that the enclosure had already fallen out of active use by the time these burials were made, the ditch partly silted, the bank reduced, the place no longer serving its original purpose but still, perhaps, carrying some significance for the people who chose to bury their dead there.