The monument sits within a low grassy mound measuring roughly 10 metres square, surrounded by fair pasture that gives way to rougher, rock-strewn ground to the north. What remains of the original tomb structure includes two impressive portal stones at the northeast end, standing 2.9 and 2.6 metres tall respectively, with a modest backstone 2.5 metres to the southwest. These weathered sentinels have watched over the inner reaches of the lough for millennia, their tops sloping downward in characteristic portal tomb fashion.

The site has clearly seen multiple phases of use throughout prehistory. Beyond the main tomb structure, archaeologists have identified secondary features including a stone cist covered by two superimposed slabs and a curious raised slab supported by four small stones. The cist, measuring 1.2 metres by 0.7 metres and 0.75 metres deep, may have served as a later burial chamber. In 1880, Bronze Age funerary pottery was discovered here, including a vase, fragments of an urn, and a small accessory vessel, though whether these came from the portal tomb or the cist remains uncertain. Earlier still, in 1846, local historian Fagan recorded that ‘two crocks of bones’ had been unearthed near the site some years before his visit.

The mound itself shows signs of more recent alterations; a hedge-grown wall runs along its western edge whilst dry-stone facing defines the southern portion of its eastern boundary. Several mature trees were planted around the edges in relatively modern times, further modifying the monument’s appearance. Despite these changes and the passage of thousands of years, the Carnaghan portal tomb remains a striking testament to the engineering skills and spiritual beliefs of Ireland’s Neolithic inhabitants, who chose this commanding position overlooking Lough Swilly as a fitting place to honour their dead.