The row stretches 8.9 metres from northeast to southwest, and the stones graduate in a way that rewards close attention: the northeasternmost is the smallest, rising to 1.2 metres, the middle stone is the tallest at 1.8 metres, and the southwestern stone sits between the two at 1.7 metres. That gradation in height, running along a precise alignment, is a recurring feature of Cork and Kerry stone rows, a monument type concentrated in the southwest of Ireland and thought to date broadly to the Bronze Age.

What makes the Cullenagh row quietly complicated is a disappearance. The Ordnance Survey six-inch map of 1842 records a fourth stone standing to the west of the middle stone. It is no longer there. Whether it was removed, buried, or simply fell and was absorbed into the ground over the intervening centuries, the record does not say. A test pit excavated roughly five metres north of the row reached basal peat, the compressed organic layer that accumulated at the base of the bog before any disturbance, and a radiocarbon determination from that peat returned a date of 975 plus or minus 45 years before present, a result published by Lynch in 1981. That figure places the peat formation in the early medieval period, though it speaks to the age of the surrounding landscape rather than necessarily to the erection of the stones themselves, which may well be considerably older.