The small stony inlet immediately to its south-east is called Portnakilly, a name that appears to derive from the graveyard itself, suggesting the burial ground shaped the landscape's vocabulary long before it was mapped or formally recorded.

The enclosure is rectangular, roughly 21 metres north to south and 26.5 metres east to west, bounded by a rubble drystone wall between one and 1.2 metres high. On the southern side, where the ground drops naturally toward the shore, the wall gives way to a stone-faced scarp whose top sits almost level with the interior ground, an elegant solution to a sloping site. The 1838 Ordnance Survey six-inch map names the place St Columbkille's Burial Ground and shows a church within the north-west corner of the enclosure; a right-angled indentation in the wall there still hints at where it stood, though no trace of the building itself remains. The same map records a separate rectangular enclosure appended to the north side of the graveyard, also now gone. Both Inishkea North and Inishkea South used this ground for burial throughout the nineteenth and into the early twentieth century, the two island communities sharing a single place of the dead across the narrow water between them.

The western half of the graveyard holds the densest concentration of graves. Plots are outlined by low settings of large stones and slabs, and a number of graves are covered with quartz cobbles and pebbles, a practice with very deep roots in Irish funerary tradition. Most headstones are plain, uninscribed upright slabs, rectangular or slightly irregular, but four graves carry crudely shaped cross-form slabs in place of the simpler markers. A low internal scarp divides this busier western section from the eastern half, where the ground levels out and the evidence of burial thins to a scatter of low upright stones and fragmentary stone settings barely visible through the grass.