What appears at first to be a modest graveyard near Rinardoo Bay is, on closer inspection, a place where several distinct phases of history have folded in on one another, each leaving traces inside the walls of the next. The D-shaped enclosure recorded on the 1838 Ordnance Survey map measures roughly 58 metres north to south and 66 metres east to west, and sits in a field that was already known then as the Church Park. By 1914, a smaller rectangular burial ground had been inserted into its centre. That inner enclosure belongs to the Smyth family of Portlick Castle, and its drystone walls, built largely of coarse local limestone, turn out to contain more than twenty squared or finely dressed stones recycled from an older structure, most likely a late medieval church that once stood on the same ground. Fragments of a splayed window aperture sit flat on the north-east section of the wall, accompanied by pieces of window surround that once formed part of the same opening. A chamfered door jamb fragment with a raised triangular stop appears at the south-west corner, and sections of pointed lancet arch are built into the west-facing wall, one visible from outside, one from within.

The site's history reaches back considerably further than the medieval period. The graveyard itself appears to occupy the bailey of a motte castle, a Norman-era earthwork fortification consisting of a raised mound with an adjoining enclosed courtyard, which stands immediately to the south. That castle may in turn have been constructed over an earlier Christian ecclesiastical enclosure, a pattern of successive reuse not uncommon in Ireland, where sacred or strategically useful ground was rarely left idle for long. Local tradition, recorded by Billy English in 1976 and corroborated in the written history of the Smyth family, holds that an early Christian church once stood here. The family history noted that members "are buried in a private cemetery formed around the ruins of an ancient chapel in front of Portlick Castle." Physical evidence supports the tradition: an early Christian cross-slab, a flat stone incised with a cross characteristic of the early medieval period, was found built into the fabric of the Smyth burial ground wall and has since been removed to the National Museum of Ireland. Another cross-slab, discovered in 1976 in an orchard wall roughly 220 metres to the north-north-west, is now missing, though it may originally have come from this same site. The Smyth family connection to Portlick dates to 1703, when Reverend Robert Smyth of Dublin purchased 190 acres here, part of what had previously been the confiscated Dillon estate, which had passed through several hands before reaching him.