Measuring 0.75 metres in height and 1.5 metres wide at its base, with a thickness of 0.38 metres, this prehistoric monument stands aligned along a northwest to southeast axis. The stone's modest proportions belie its significance as one of many such ancient markers scattered across the Donegal countryside, each one a tangible link to the island's distant past.

Standing stones like this one remain some of Ireland's most enigmatic archaeological features. Whilst their exact purpose continues to spark debate amongst archaeologists, they likely served multiple functions for the communities who erected them during the Bronze Age, roughly between 2500 and 500 BCE. Some may have marked burial sites or territorial boundaries; others possibly served astronomical purposes, marking significant solar or lunar events throughout the year. The northwest to southeast orientation of the Millford stone might suggest some celestial significance, though without extensive archaeological investigation, its original purpose remains speculative.

The stone's survival through thousands of years speaks to both its robust construction and the respect afforded to it by generations of local inhabitants. Documented in the comprehensive Archaeological Survey of County Donegal, compiled by Brian Lacey and his team in 1983, this monument forms part of a rich tapestry of field antiquities that chronicle human presence in Donegal from the Mesolithic period through to the 17th century. Today, it continues to punctuate the rural landscape, a reminder that even the most unassuming features of the Irish countryside often harbour profound historical depth.