Set into a round-arched embrasure in the south wall, the flat-headed entrance is capped with a reused Early Christian cross-slab, a carved stone that predates the medieval church itself and was repurposed, probably in the post-medieval period, as building material. It is a quietly unsettling detail: a devotional object absorbed into the fabric of a later structure, its original context dissolved, its carved face now holding up a doorway into a roofless nave thick with ivy.

The site has a long and layered past. The monastery of Lecan-Midhe stood here before the medieval church was ever built, and the Annals of Ulster record the death of Fursa, abbot of Lecan Midhe, in 750. The house was associated with St. Cruimín, said by the scholar John O'Donovan to have founded it; two feast days were kept in his memory, one on 28th June and a second, noted in the Martyrology of Tallaght, on 29th December. The medieval church that eventually rose on this ground was later drawn into the orbit of the Augustinian Abbey of Tristernagh when, during the reign of Edward I (1272 to 1307), a local landowner named Adam de Ledwyche granted Tristernagh the church of Lekkyn, as Lackan was then rendered. The Ledwith family connection did not end there: the chancel, the shorter eastern arm of the church separated from the nave by a now-blocked dividing wall, appears to have been converted into a private burial enclosure for the family in the nineteenth century, and a headstone to Andrew Ledwith of Streamstown survives inside it.

What remains today is fragmentary but legible. The ivy-covered south wall of the nave stands to roughly 3.6 metres and runs for 8.6 metres; a short section of the chancel's south wall survives beside it. The east and west gable walls are gone entirely. Beside the cross-slab lintel, the south wall also contains a single-light ogee-headed window, its elegant pointed-arch head a marker of late medieval craftsmanship, located two metres east of the doorway. The north wall of the church has been absorbed into the graveyard boundary and is buried under brambles. Trees at both ends of the ruin obscure what little else might remain.