These megalithic structures, likely passage tombs, were part of a larger archaeological complex that included at least three distinct sites. Sites B and C, which stood about 120 metres west of Site A, have long since been removed, though they were still visible enough to be recorded on Ordnance Survey maps in the 1840s. Thomas Fagan, who documented them between 1845 and 1848, described both monuments as being constructed with stones ranging from 0.6 to 1.05 metres in height. One measured approximately 3.3 metres long by 1.4 metres wide, whilst the other was smaller at 1.8 metres long by the same width; both had apparently been larger originally.

Site B appears to have been a passage tomb set within a circular cairn, possibly with a kerbed edge, whilst Site C, marked as ‘Cromlech’ on early field maps and situated about 10 metres northwest of Site B, was shown as a small cluster of dots that might represent a chamber. Given their proximity and similar construction, archaeologists believe both were likely passage tombs, part of what’s now recognised as the Kilmonaster Passage Tomb cemetery. The complex caught archaeological attention again in 2005 when pre-development testing was required for agricultural buildings near one of the surviving monuments, though these investigations revealed little beyond modern pottery sherds, a single worked flint in the topsoil, and some animal bones from livestock burials along an old field boundary.

Today, whilst Sites B and C exist only in historical records and archaeological surveys, the broader Kilmonaster complex remains an important example of Donegal’s Neolithic heritage. The detailed observations made by Victorian antiquarians like Fagan, combined with more recent archaeological work, help piece together the story of these lost monuments; structures that once dominated the local landscape and gave rise to folklore about giants’ resting places.