This substantial monument, measuring 12 metres along its northeast to southwest axis and 5.5 metres wide, rises to 1.25 metres at its western end before gradually tapering down towards the east. Its construction reveals careful planning; whilst the bulk of the structure consists of smaller stones, the builders deliberately placed larger stones around the perimeter to define and strengthen the cairn's distinctive oval shape.

The cairn's prominent position overlooking Lough Swilly suggests it held particular significance for those who built it, though its exact purpose remains unclassified by archaeologists. Such monuments in Ireland often served multiple functions; as burial sites, territorial markers, or ceremonial spaces, and this example at Ballynarry likely dates back thousands of years. The careful selection of its elevated location would have made it visible from considerable distances, marking this spot as important to the ancient communities who inhabited this part of Donegal.

Today, the cairn continues to dominate its pastoral setting, having survived centuries of weather and agricultural activity in the surrounding fields. Its documentation in the Archaeological Survey of County Donegal helps preserve knowledge of this monument for future generations, ensuring that even as the landscape around it changes, the story of this carefully constructed stone mound endures as part of Ireland's rich archaeological heritage.