It measures roughly 3.75 metres across and rises to a maximum height of about 20 centimetres, barely enough to cast a shadow. At its centre sits a hollow approximately 70 centimetres wide, a detail that quietly signals something has been disturbed here at some point in the intervening millennia. This is Site E, a cairn, meaning a deliberate accumulation of stones marking a significant spot, rather than field clearance or casual dumping, and it belongs to a period of human activity on this hillside stretching back thousands of years.

The site was documented by Rynne and Ó hEailidhe in 1965, whose survey noted the roughly circular form, the absence of any kerb stones around the perimeter, and that central hollow suggesting earlier interference, whether by curious locals, opportunistic diggers, or simple erosion over time. What makes the cairn more than a minor curiosity is its context. It forms part of an extensive settlement and cemetery complex of Late Neolithic and Early Bronze Age date on Piperstown Hill, a period broadly spanning from around 4000 to 1500 BC when communities in Ireland were burying their dead, marking landscapes, and establishing presences on upland ground that later centuries largely abandoned. Site E is one node in what was evidently a much larger arrangement of human occupation on these slopes.

Piperstown Hill sits within the Dublin Mountains, accessible from the southern fringes of the city. The cairn lies on the southern slopes of the hill, and the terrain is open upland, so reasonable footwear is advisable. Because the monument is so low-lying, it is easy to miss without some foreknowledge of its location and approximate dimensions. The central hollow is the most distinctive feature to look for once you are in the right area. Visibility across the site is best outside the growing season when vegetation is lower. There are no facilities or formal access infrastructure, and the cairn sits within a broader archaeological landscape, so it rewards slow, attentive walking rather than a quick pass.