Measuring 2.46 metres in height and oriented along a northeast to southwest axis, this ancient monolith stands as it has for thousands of years; its base spans 81 centimetres in width whilst tapering to approximately 50 centimetres in thickness. The stone's deliberate placement and careful orientation suggest it held significant meaning for the prehistoric communities who erected it, though its exact purpose remains one of archaeology's enduring mysteries.

Standing stones like the one at Cooly are found throughout Ireland and typically date from the Bronze Age, roughly 2500 to 500 BCE. These monuments served various functions in ancient society; some marked territorial boundaries or burial sites, whilst others may have had astronomical significance, aligning with celestial events such as solstices or lunar cycles. The northeast to southwest orientation of this particular stone could indicate such an astronomical connection, though without extensive archaeological investigation, its original purpose remains speculative.

Today, the Cooly standing stone continues its quiet vigil in the Donegal landscape, a tangible link to Ireland's prehistoric past. Its presence in an active pastoral setting demonstrates the remarkable continuity of land use in rural Ireland, where modern farming practices exist alongside monuments that predate recorded history. For visitors interested in Ireland's archaeological heritage, this unassuming pillar offers a chance to literally touch the deep past, standing in the same spot where ancient peoples once gathered for purposes we can only imagine.