The Carlow Archaeological and Historical Society guided the Ballon Hill Archaeology Project, culminating in 2014, in the publication of an outstanding and comprehensive report on the Bronze Age burial site on Ballon Hill.
The full report is available from CAHS. In the meantime you can download a PDF of an article outlining the study's findings, published by the Journal of the Royal Society of Antiquaries of Ireland, Vol. 146 (2016), pp. 5- 20 Published by: Royal Society of Antiquaries of Ireland, here.
'Ages' such as the Neolithic and Bronze Ages did not have clearly defined boundaries either in time or geography. (In some parts of the world, people remained using stone technologies until recent centuries, for example.) This study puts the start of usage of the Ballon Hill Bronze Age burial site at 2,200BC, i.e. 4,200 years ago. The cromlech that we are focussed on in Ballon village comes from the Neolithic Age, and was most likely installed at least 5,000 years ago. The sense that the entire area from the reserve plot where the cromlech and ceremonial site was across the East side of Ballon Hill might have been a contiguous ceremonial site, is inescapable.