Once recorded as a visible mound, it now leaves no surface trace whatsoever, which places it in an odd category of archaeology: sites that are known to exist, whose general location is documented, but which have nothing left to show the eye.

A fulacht fia, for those unfamiliar with the term, is a type of ancient outdoor cooking place found in enormous numbers across Ireland, typically dating from the Bronze Age. The usual form involves a trough, a hearth, and a horseshoe-shaped mound of fire-cracked stone and charcoal, the accumulated debris of repeatedly heating stones and dropping them into water to boil it. They are almost always found near streams or marshy ground, and the example at Knockburden fits that pattern precisely, sitting beside its watercourse in what is now pasture. A six-inch Ordnance Survey map produced in 1940 recorded a mound at this location, which suggests the site was still physically legible within living memory. At some point between that survey and more recent inspection, the mound ceased to be visible, most likely through the ongoing effects of agricultural land use.