These circular depressions, carved into the stone surface by prehistoric inhabitants, represent one of Ireland's more subtle archaeological treasures. The site at Carrowreagh, also known as Craignacally, was documented by researcher Van Hoek in 1988, who noted its position relative to the purported burial ground nearby.

Cupmarks like these are amongst the most common forms of rock art found across Ireland and Britain, typically dating from the Neolithic to the Bronze Age periods, roughly 4000 to 1500 BCE. These deliberate hollows, usually measuring between 2 and 10 centimetres in diameter, were painstakingly pecked into the rock face using stone tools. Whilst their exact purpose remains a mystery, archaeologists have proposed various theories; some suggest they held ritual significance, perhaps for offerings or ceremonies, whilst others believe they may have served as territorial markers or even primitive star maps.

The Carrowreagh site forms part of a broader pattern of rock art scattered throughout Donegal's hills and valleys. The county boasts numerous examples of prehistoric carvings, from simple cupmarks to elaborate cup and ring marks, spiral designs, and other geometric patterns. These ancient artworks offer a tangible connection to Ireland's earliest communities, who left their mark on the landscape thousands of years before written history began. Though modest compared to more elaborate rock art sites, these two cupmarks stand as enduring testimony to human presence in this corner of Donegal stretching back millennia.