This stone is not marked on the OS but is easy to find and well worth checking out. I would recomend seeing it just after some rainfall as the deep red stone is quite beautiful when wet.
It stands quite picturesquely in east the shadow of The Great Sugar Loaf mountain, but unpicturesquely next to a makeshift football pitch and beneath power lines.
The stone is 1.6m tall, 60cm wide and 30cm deep.
Take the N11 south from Dublin until you come to Kilmacanoge. Turn right onto the R755 and then left just after the post office. About 900m along this road you should see the stone through a gate on your right.
This is an explanation of (and a bit of a disclaimer for) the coordinates I provide.
Where a GPS figure is given this is the master for all other coordinates. According to my Garmin these are quite accurate.
Where there is no GPS figure the 6 figure grid reference is master for the others. This may not be very accurate as it could have come from the OS maps and could have been read by eye. Consequently, all other cordinates are going to have inaccuracies.
The calculation of Longitude and Latitude uses an algorithm that is not 100% accurate. The long/lat figures are used as a basis for calculating the UTM & ITM coordinates. Consequently, UTM & ITM coordinates are slightly out.
UTM is a global coordinate system - Universal Transverse Mercator - that is at the core of the GPS system.
ITM is the new coordinate system - Irish Transverse Mercator - that is more accurate and more GPS friendly than the Irish Grid Reference system. This will be used on the next generation of Irish OS maps.