A fulacht fia, the term used for these ancient outdoor cooking places, typically consists of a horseshoe-shaped or oval mound of burnt and fire-cracked stone, accumulated over repeated use of a nearby trough in which water was heated by dropping in fire-heated rocks. The mound at Farranistick is oval, measuring roughly 19.8 metres north to south and 15 metres east to west, and rises only about 0.7 metres above the surrounding ground. It does not appear on aerial photography, and no trace of it shows on the Ordnance Survey maps of 1837 or 1913. To all outward appearances, there is nothing there at all.

What gives the site away is what lies just below the surface. When probed in 1980, a large amount of stone was detected at every point tested across the mound, suggesting the dense subsurface deposit that is characteristic of heavily used fulacht fia sites. The land here was originally low-lying and boggy, the kind of waterlogged ground that Bronze Age communities often chose for this type of activity, since a ready water source was essential to the process. The site has a near neighbour: a second fulacht fia lies roughly 180 metres to the south-east, and the researcher Victor Buckley, who recorded fulacht fiadha extensively across Ireland, identified this one as Fulacht Fiadh No. 2 on his sketch map of the area. The clustering of two such monuments in close proximity is not unusual; some parts of the Irish midlands are dense with them, though many, like this one, have been quietly absorbed into the agricultural landscape.