This is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically consisting of a horseshoe-shaped mound of burnt and shattered stone built up around a water-filled trough. The monument at Knockans, in County Clare, sits where the land just begins to lift above the marsh, a position that would have made practical sense to whoever used it, given that fulachtaí fia rely on a ready water supply.

The site measures roughly 12 metres north to south and 11 metres east to west, with a surviving arc of bank running from the north-east around to the south-east. The bank stands approximately 0.9 metres on its interior face and around a metre on the exterior, which gives some sense of the accumulated material, broken stone repeatedly heated in fire and dumped after use. The western side of the monument has merged into the slightly higher ground behind it, so the shape is irregular rather than the clean crescent sometimes seen at better-preserved examples. A central hollow, perhaps 5.5 metres across, may have opened to the north or south, and several loose stones near the north-west are thought to have been displaced from what was once a trough, with a larger stone still sitting at the south-west. Tom Coffey first identified the site in 1994. What makes the location additionally notable is that a second fulacht fia lies roughly 125 metres to the north-east, suggesting this wet, marginal ground was returned to repeatedly, or used by more than one group over time.