These sites, which date broadly from the Bronze Age, typically consist of a horseshoe-shaped mound of burnt and broken rock accumulated over repeated use of a trough filled with water, heated by dropping stones from a fire into it. The Cummer example, recorded as a mound of broken and burnt sandstone, has since lost its precise location to agricultural development.

The site was documented by Kinahan between 1879 and 1888, who noted the mound sitting just thirty metres south of a ring-cairn, a circular monument of piled stones that would have made the area significant in prehistoric terms. What makes the setting quietly suggestive is the cluster of features that once converged here: the cairn, the fulacht fia, and a nearby water source known as the Druids Well. The fulacht fia occupied a favourable position on a south-facing slope, just below a col, the low saddle between two hills lying roughly four hundred metres to the west and east and some forty to fifty metres above. At the time of Kinahan's observation, the area still formed a concentrated settlement; by the time of the modern record, it had been absorbed into a farmyard, and the mound's exact position within that space had become impossible to pin down.