Each one measures roughly nine metres by six metres, and together they represent what was once an organised industrial operation: the production of charcoal on a considerable scale. Charcoal-making required flat, prepared ground on which to stack and slowly smoulder timber under a covering of earth and turf, a process that could take days to complete and demanded careful tending. These platforms, known sometimes as pitstead or hearth platforms, are the physical traces left behind once the ground had been repeatedly scorched and compacted by that work.

More than seventy of these platforms have been recorded on the northern and southern sides of the Upper Lake, as well as to the west and south-west of Reefert Church, the remains of a small Romanesque church associated with the early monastic settlement at Glendalough. A further forty similar platforms have also been noted in the area. Scholarly attention to the site dates at least to 1940, when Ua Riain documented the platforms, with later work by Healy in 1972 confirming and expanding on the record. The number of platforms suggests this was no casual or occasional activity but something carried out repeatedly and systematically across the valley. The proximity to the monastic site at Glendalough raises the possibility of a connection, though the precise dating and purpose of the charcoal production remains less than certain.

The platforms lie within the Glendalough valley in County Wicklow, and the area around Reefert Church and the Upper Lake is accessible via the well-worn paths of the Glendalough site. The platforms themselves are subtle features, and most visitors pass them without a second glance. Knowing to look for low, slightly levelled ovals in the ground, particularly on the slopes flanking the lake, gives the landscape a different quality entirely.