You can drive right up to this mountaintop cairn, though I suggest you wait until the cloud clears, unlike us who drove up in maybe 10 metre visibility and a force 10 gale. There is a huge mast up here, hence the road, and the howls as the wind blew through it added to an already spooky atmosphere.
The cairn, said to be a passage grave (see archaeology.ie entry) is about 3 metres high. Much of it is now grass covered, though there are patches where its true nature is still visible. There are quite a few larger stones around, though I couldn't make head nor tail of these, battling as I was with the driving mist of low cloud.
I would say that the views from here are spectacular but we couldn't see to confirm that. As it's a driveable climb, I may re-visit here some day to check.
This circular hilltop cairn, 21m in diameter and over 4m in height, contains the remains of a megalithic structure 3.5m long, in the SW quadrant. It is open to the SW and narrows from 1m wide to 0.5m at the rear. Three lintels are in position; the rear 0.7m of the structure is corbelled. The remains would seem to be those of a passage-tomb of uncertain design. Near the centre of the cairn are the remains of a drystone-walled circular structure, 3.3m in diameter, with an entrance passage opening to the SE, which may have been built by Lord Clermont. (CLAJ 1941, 77-9; Herity 1974, 232).