A faint but distinct difference in the growth of vegetation marks a spread of dark, charcoal-rich soil roughly eight metres east to west and six metres north to south, and that soil is the flattened remnant of a burnt mound, a type of prehistoric site found widely across Ireland and Britain.

Burnt mounds, sometimes called fulachtaí fia in Irish, are among the most common prehistoric monuments in the Irish landscape, yet they remain poorly understood. The prevailing theory holds that they were cooking sites, where stones were heated in fire and then dropped into water-filled troughs to bring the water to a boil, though uses related to bathing, brewing, or craft processes have also been proposed. The cracked, fire-shattered stones and charcoal-blackened soil that characterise these sites are precisely what survive here at Mauteoge, even though the original mound has long since been levelled, whether by ploughing, land clearance, or the slow pressure of agricultural use over centuries. What remains is essentially a stain in the earth, its edges not entirely clear but visible enough that the grass grows differently above it. Notably, a second burnt mound sits approximately twenty metres to the north, suggesting this area of wet ground attracted repeated or concurrent use, since access to water was a practical necessity for the activity these sites represent.