It was never meant to be found at all; it came to light only because a pipeline happened to pass through the area. When it did, the discovery was significant enough that the pipeline route was subsequently rerouted to avoid disturbing the monument further.

Burnt mounds are among the more enigmatic features of the Irish prehistoric landscape. They are crescent or kidney-shaped accumulations of fire-cracked stone and charcoal, typically found near water or in boggy ground, and they appear across Ireland in considerable numbers. Their purpose is still debated; heating water for cooking, bathing, or industrial processes such as tanning or textile production have all been proposed. The Treannaskehy example was identified during archaeologically monitored works on the Lough Mask Regional Water Supply Scheme between 2001 and 2002. A layer of burnt sandstone and charcoal, roughly thirty centimetres thick, was exposed, and its full extent remained uncertain since the deposit continued southward beyond the area examined. The visible spread was estimated to cover a roughly circular area of ten to eleven metres in diameter. A charcoal sample was taken and radiocarbon dated, returning a result of 2734 plus or minus 40 years before present, placing the activity at this spot somewhere between 991 and 813 BC, during the Late Bronze Age. What makes this particular location quietly remarkable is not that a single burnt mound was found here, but that at least two others lie close by, one approximately sixty metres to the north-east and another around a hundred metres to the south-west. Three such sites clustered within a short distance of one another in the same wet ground suggests that this was a place returned to repeatedly, perhaps across generations, for purposes we can only partially guess at.