The church measures just 10.3 metres long and 4.5 metres wide, oriented east to west in the usual manner, and of its fabric only a plain doorway in the north wall and the Morris family tomb in the interior have survived in any meaningful form. What makes the site unusual is not the ruin itself but the constellation of related features that surrounds it, each one pointing to a pattern of localised veneration that outlasted the building.

The church was dedicated to St Flannan of Killaloe, the seventh-century bishop associated with the diocese of Killaloe in County Clare, which suggests a reach of influence that extended well into the west of Connacht. The oldest section of the graveyard surrounding the church is oval in plan, a shape often associated with early ecclesiastical enclosures that predate the formal Norman organisation of parishes. To the south of the church stands a leacht, a low commemorative or penitential structure built of drystone, here consisting of a wall roughly two and a half metres long with a niche set into the natural slope of the ground. About a hundred metres to the east of the graveyard lies a large natural boulder known as St Flannan's Bed, and a holy well sits to the southwest. These features, taken together, suggest a site that functioned as a place of pilgrimage or pattern, where movement through the landscape was as much a part of the practice as prayer in the church itself. A further detail connects the site to its immediate surroundings in an unexpected way: during renovations at Errislaannan Manor, roughly 170 metres to the north-east, a small carved fragment was found depicting a robed figure in relief, its head missing, standing about 25 centimetres tall. It is considered possible that this piece originated at the church, its displacement across the years as unexplained as the figure's absent face.