This is a univallate rath, meaning a ringfort enclosed by a single earthen bank rather than multiple defensive ditches, and its internal diameter of 42.5 metres would once have made it a substantial enclosure by any measure. A small stream cuts northeast through a deep ravine just to the southeast, adding a natural boundary to what was already a deliberately chosen position on the landscape.

The rath's condition today tells a layered story of survival and erasure. The enclosing bank has been completely levelled across a wide arc from east through south to south-southwest, and for a shorter stretch at north-northwest, agricultural clearance or field improvement having done away with much of the original earthwork. In the northeast quadrant, a later field bank now marks the line of the enclosure, but the original bank can still be detected beneath it, protruding roughly two metres beyond the outer face of the field bank for a stretch of twenty-four metres and rising to about 1.2 metres in height. The western sector has fared best, with the bank still standing some 1.5 metres high. Two breaks interrupt this western stretch, though whether either corresponds to the original entrance into the enclosure remains uncertain. The description comes from J. Cuppage's 1986 archaeological survey of the Dingle Peninsula, Corca Dhuibhne, a foundational study of one of Ireland's most densely layered prehistoric and early medieval landscapes.

What survives at Glannaheera is less a monument than a puzzle in earth and stone, where centuries of farming have overlaid the original structure with their own logic. The western arc remains the most legible section, and standing there, with the ravine below and the mountain spur rising behind, something of the site's original character still comes through, even if the entrance that once gave onto all of it has long since been lost to guesswork.