The Shanganagh Dolmen sits in a low-lying green area at Ballybrack, just off the Shanganagh-Bray road, surrounded by the ordinary geometry of suburban life. It is the kind of juxtaposition that takes a moment to fully register: a structure built to house the dead in the Neolithic period, now flanked by parked cars and front gardens.

A portal tomb is a type of megalithic monument typically consisting of two upright portal stones at the entrance, sidestones forming the chamber walls, and a large capstone laid across the top; they are among the oldest surviving human constructions in Ireland. This example is built entirely in granite. The roofstone, which slopes noticeably, measures roughly 2.2 metres long by 2.05 metres wide and is estimated to weigh around 12 tonnes. When the antiquarian Henry O'Neill described it in 1852, he noted that one of the supporting stones had broken off at the middle and another had fallen inward, giving the structure the slightly precarious look it still presents today. The chamber itself faces east, running about 1.89 metres long and 0.76 metres wide; O'Neill reckoned it would originally have stood around 1.5 metres high. There are no traces of any covering cairn, the mound of stones that sometimes enclosed such tombs, which means the monument has long stood exposed and unadorned. It has been referenced in the archaeological literature since at least 1897, when Borlase recorded it, and again by Ó Nualláin in 1983.

The tomb is accessible within the housing estate at Ballybrack, set on a small green where it can be approached on foot without any particular difficulty. Because it sits at ground level in an open residential area, there is no dramatic approach and no viewpoint from which it dominates the landscape; the experience is almost entirely one of proximity. Getting close and crouching to look into the narrow chamber, or examining the rough underside of that enormous capstone, is where the monument makes its impression. For those who want to examine the structure in more detail before or after a visit, a 3D model is available online at skfb.ly/oJtSp.