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.