Known in Irish tradition as a cillín (pronounced roughly "killeen"), this was a burial place for infants who, under Catholic teaching, could not be interred in consecrated ground. Such sites are scattered across the Irish countryside, often quiet and half-forgotten, their graves marked not with inscribed headstones but with plain, wordless stones that barely break the surface of the soil.

The enclosure at Cloonygowan measures roughly 16 metres north to south and 23 metres east to west. Inside, small subrectangular burial plots are outlined by stones, with upright slabs at either end and, in some cases, flat slabs laid across the interior. Boulders placed on top of smaller stones serve as additional grave markers. When the site was inspected in 1988, large pieces of quartz were found resting on top of some graves, a practice with deep roots in Irish folk belief, where quartz was associated with protection and the marking of sacred space. A later inspection in 1998 found that the southern and western sides, previously edged only by a loose line of stones, had been fenced off with a post and wire fence. Much of the interior is now strewn with loose stones and obscured by overgrowth, with trees crowding the perimeter. A modern farm shed sits adjacent to the south-western corner, and a farmstead lies immediately to the north-east. Fifteen metres to the north-west stand the ruins of a possible church and a bullaun stone, a boulder with one or more basin-like depressions ground into its surface, which are found at early ecclesiastical sites across Ireland and were sometimes used for water, ritual, or grinding.