A ring-barrow is a prehistoric burial or ceremonial monument, typically a low circular mound or platform enclosed by a ditch and an outer earthen bank. This one, eight metres in diameter, shares parts of its perimeter with its neighbours: where its own fosse and bank would ordinarily run, the monument instead borrows the ditch of an adjacent bowl-barrow to the north-west and the fosse of a large enclosure to the south. The effect is of a site knitted into a wider landscape of the dead, its edges quietly dissolving into older or contemporary earthworks rather than standing apart from them.

The hill at Longstone carries an unusual concentration of prehistoric remains. The ring-barrow sits against the inner south-south-east side of a multi-period enclosure, with two further ditch-barrows within metres of it. Look outward and the horizon offers more: a standing stone 800 metres to the north-east, a large barrow roughly a kilometre and a half to the west-south-west, and a mound-barrow about 1.8 kilometres to the south. The panoramic position was almost certainly deliberate. Hilltop placement is a recurring feature of Bronze Age funerary monuments across Ireland, suggesting that visibility, both of and from these sites, carried meaning for the communities that raised them. The structural elements of this particular barrow, its scarped edge, fosse, and external bank, survive in good condition with crisp breaks of slope and little sign of livestock damage, which is relatively unusual for a monument of this age and exposure.

The interior of the ring-barrow is level, dry, and clear of vegetation, but reaching it is another matter. Dense gorse has spread through the fosse and over the external bank, making access genuinely difficult and obscuring much of the monument's outer profile. Visitors prepared for a push through scrub will find the hilltop itself rewarding for the sheer density of earthworks gathered there, each one slightly different in form and each one sharing space, sometimes literally, with the next.