The site consists of a single, closed, roughly rectangular chamber, defined on north and south by two large side stones which lean inwards to rest on two much smaller end stones. It is set almost centrally within an irregular cairn around 12.5m long, perhaps originally circular but subsequently damaged by cultivation. The chamber was once covered by a massive capstone but this has been displaced and broken in two. A large upright stone stands immediately to the north-west of the northern side stone and projects around 1.2m above the cairn. Originally a matching upright stood on the outside of the southern side stone but this has been pushed over by the weight of the capstone and leans out of position.
The chamber was excavated in 1934 but had already been badly disturbed and the only finds were two small sherds of prehistoric pottery, one bearing square-toothed comb impressions, and a polished stone bead.
This is a difficult monument to classify. It has been interpreted as a portal tomb, with the flanking uprights representing the portal stones defining the entrance, but these usually stand at one end of the cairn and within the side stones of the chamber rather than outside. The closed rectangular chamber set within a relatively small cairn looks more like some form of megalithic cist, but what then is the function of the uprights flanking the western side of the chamber. A third alternative, suggested by the excavators in 1934, is that the monument represents a transition between the more complex tombs of the Neolithic period and the simpler, small scale, cists of the Bronze Age. Under this interpretation the flanking stone echo a court type feature but enclosed within the body of the cairn rather than forming an entrance. The rectangular chamber itself then represents an early form of cist grave, but built of large stones and set above ground in contrast to the below ground, box-like monuments so typical of the Early Bronze Age.
This unusual monument, together with a second megalith around 750m to the north, has long been an object of curiosity. Both had apparently been disturbed before 1816, when John Bell, who investigated several of the monuments in the area, noted that their enclosing cairns had been partially removed – although one had been perfect until two years earlier. An 1880 account provides more detail and suggests that this southern monument, already noted as ‘of an unusual type’ looked much as it does today, with the capstone displaced to expose the rectangular chamber. The report also suggests that the northern tomb had provided a convenient source of stone during the building of nearby Killevy Castle earlier in the century. A second report, written four years later, lists this southern tomb under the heading of Kists etc and notes that it was ‘regarded with superstitious reverence’ by the local population.