These are the remnants of an industrial past, the quiet evidence of charcoal production at a scale that required serious organisation and considerable labour.

Charcoal-making platforms of this kind, sometimes called hearths or pitsteads, were created by levelling a roughly oval area of ground, typically on a slope, where timber could be carefully stacked and covered with earth or turf and then slowly burned in a low-oxygen environment to produce charcoal. The resulting fuel was essential for smelting and metalworking long before coal became widely available. At Sevenchurches, which is the older name for the Glendalough valley, at least 75 such platforms have been recorded on the northern and southern sides of the Upper Lake and to the west and south-west of Reefert Church, a small Romanesque ruin that dates to the early medieval period. Each platform measures roughly nine metres by six metres. A further 40 similar platforms were noted in a separate account, suggesting the operation here was extensive, perhaps serving ironworking industries in the wider Wicklow uplands. References to the site appear in work published as far back as 1940, with a later account from 1972 confirming the scale of what survives.