A fulacht fia, to use the general term, is a prehistoric cooking site, typically consisting of a horseshoe-shaped or oval mound of burnt and fire-cracked stone accumulated beside a water source over repeated use. The theory most widely accepted is that stones were heated in a fire, then dropped into a trough of water to bring it rapidly to the boil, cooking meat or perhaps serving other purposes. What survives at Monanooag is an oval mound of burnt material, sitting in low-lying rough pasture where limestone outcrops through the turf, with a marshy area lying just to the south.

The mound measures roughly 7.9 metres north to south and 4.8 metres east to west, rising to about 0.65 metres at its highest point. Those are modest but respectable dimensions, enough to represent a considerable accumulation of activity over time. The marshy ground to the south is characteristic of the type; fulachta fia are almost always found close to a reliable water source, and the poorly drained, low-lying ground here would have provided exactly that. The site was recorded by Denis Power and uploaded to the national record in August 2011. There is, however, a slight hollow at the northern end of the mound, measuring roughly a metre by 1.2 metres and about 0.4 metres deep, which was not made by prehistoric hands. It was caused by a mechanical digger, a reminder that even legally protected monuments are vulnerable to accidental or incidental disturbance from modern agricultural machinery.

The mound sits in rough pasture, and the western side is noticeably masked by vegetation overgrowth, which means the full extent of the monument is not immediately legible from a casual glance. Anyone visiting should look for the low rise of dark, stony material characteristic of burnt-mound sites, and bear in mind that the ground surrounding it is likely to be wet underfoot, particularly in the wetter months. Stout footwear is sensible. The outcropping limestone in the surrounding field is itself worth a moment's attention, giving the landscape an austere, textured quality that frames the monument in its proper geological context.