A low, grass-covered rise in the upper Araglin valley might pass completely unnoticed underfoot, and for a long time it did. Only when a pipe trench was cut through the slope in 1996 did the mound reveal its interior: burnt and broken stone packed into a black matrix, the unmistakable signature of a fulacht fiadh. These features, found in their thousands across Ireland, are among the most common prehistoric monuments in the country, and among the least understood. The prevailing theory holds that they were cooking sites, where stones were heated in a fire and then dropped into water-filled troughs to bring the contents to a boil. The accumulation of cracked, heat-spent stone, discarded after each use, forms the characteristic horseshoe-shaped mound. At Coumaraglinmountain, that mound measures roughly twenty metres north to south and fifteen metres east to west, rising only about thirty centimetres above the surrounding ground, which is why it remained invisible until the ground was cut open.

The site sits on a north-west-facing slope in the valley of the upper Araglin river, a location that fits the typical pattern for burnt mounds: close to a reliable water source, on low or gently sloping ground. The exposure during pipe-laying work is itself a familiar story in Irish archaeology, where infrastructure projects have frequently been the occasion for accidental discovery. The monument forms part of a wider complex at Coumaraglinmountain, afforded protection under a national monuments preservation order made in 1996, the same year the trench brought it to light.