In a Kildare landscape divided between tillage and pasture, a circular earthen mound sits on a low north-south ridge, its sides partially overgrown and quietly absorbed into the agricultural routine around it. What makes it quietly anomalous is the evidence written across its surface: old cultivation ridges running northeast to southwest, cutting across the mound's flanks, suggesting that at some point farmers worked the ground right up against it, and perhaps over it, without it ever quite disappearing beneath the plough.

The mound measures roughly 22 metres across at its base, narrowing to about 5.5 metres at its flattened top, and stands approximately 4 metres high, with gently sloping sides. These proportions are consistent with a burial mound or barrow, a category of monument found throughout Ireland and dating in many cases to the Bronze Age or earlier, though without excavation the precise origin and function of this particular example remains unconfirmed. What aerial photography from 2005 confirmed is that the mound is clearly visible from above, sitting on its ridge as a distinct, rounded feature in the field pattern. The name Firmount itself, like many Irish townland names, likely preserves some memory of the feature, the element "mount" being a recurring indicator in placenames where an earthwork or raised ground was locally significant enough to anchor a name across centuries of land use.