It is a barrow, a prehistoric burial monument, and its dimensions are modest but precise: roughly eleven metres across and a metre high, ringed by a shallow external ditch about one and a half metres wide. That encircling ditch, known as an annular ditch, is what distinguishes this type of monument from a simple earthen rise, and it hints at deliberate, ceremonial construction rather than any natural accumulation of soil.

Barrows of this kind are found across Ireland and date broadly to the Bronze Age, though some examples span earlier or later periods. They were typically raised over the remains of the dead, sometimes covering a central burial pit or stone cist, and the surrounding ditch would have been cut to provide material for the mound itself. The one at Blessington sits on a slight rise in gently undulating ground, with higher terrain to the north-west, a position that, while not dramatically elevated, would have given the monument a degree of visibility within its immediate setting. Whether that prominence was intentional is the kind of question archaeology rarely answers with certainty, but the choice of even a modest eminence for such structures was rarely accidental.