No mound breaks the surface, no depression marks the turf; the site exists, as far as the eye is concerned, not at all. A fulacht fia is a type of prehistoric cooking site, typically consisting of a burnt mound of fire-cracked stone beside a trough that would have been filled with water and heated using stones dropped from a fire. They are among the most common archaeological monument types in Ireland, yet they remain poorly understood, their exact social function still debated. This one, at Coan, adds another layer of obscurity by having left no visible trace whatsoever.

The site sits in an area characterised by old dried-up stream beds, with a live stream running approximately forty metres to the east. That waterlogged, low-lying topography is exactly the kind of setting in which fulachta fia tend to cluster; ready access to water was essential to how they functioned, and boggy ground has often preserved the organic and charred material they contain. The Coan example was identified by Prendergast in a survey published in 1977, which means its existence is known only through that earlier fieldwork rather than through anything a casual observer could confirm on the ground today. The reclamation of the surrounding grassland may account for why the monument has been effectively flattened into invisibility.