The outline is almost circular, roughly 76 metres north to south and 68 metres east to west, which puts it at the larger end of what archaeologists classify as a rath, the earthen version of the more familiar ringfort. These were the enclosed farmsteads of early medieval Ireland, typically dating from somewhere between the sixth and tenth centuries, built to define a household's territory and offer a degree of security for people and livestock alike.

What survives at Ballyguyroe is modest but legible. The enclosing bank stands only 0.2 metres above the interior ground level and about 0.3 metres above the exterior, so it reads more as a suggestion than a fortification at this point. Outside it, on the arc running from the east-northeast around to the south, a fosse, which is simply a ditch dug to heighten the effective height of the bank above it, reaches a maximum depth of 1.1 metres, shallowing out to a mere depression on the remaining stretch. An entrance survives to the northwest, though it has been widened at some stage, and there is a more recent break in the bank to the east-northeast, probably made for agricultural access. Around 90 metres to the west lies a separate enclosure that has been tentatively identified as an early ecclesiastical site, a proximity that was not unusual in early medieval Ireland, where secular and religious settlements sometimes developed in close relation to one another.