The building sits at roughly the centre of an older ecclesiastical enclosure, a characteristic arrangement for early Irish church sites where a roughly circular or oval boundary marked out sacred ground. What makes the Tarramud church particularly worth attention is the evidence it carries of more than one building phase, and of an interior arrangement that was far from typical.

When a visitor named Redington examined the site in 1912, he found it in what he described as an almost perfect state of preservation, though even then the lintel of the doorway had been dragged out and broken, and its stones lay scattered on the ground. The doorway itself, set at the west end of the south wall, was notable for its square-headed form, an unusual choice, with jambstones decorated with roll and line mouldings and diagonal tooling. Overhead, fragments of a relieving arch survive, an arch built above a lintel to distribute the weight of the wall and protect the opening below. Round-headed lancet windows, deeply splayed to draw in light, are visible in the east gable and towards the east end of the south wall. Redington dated the main structure to the twelfth century, but he suspected that the north wall and some of the larger boulders incorporated into the other walls belonged to an earlier building on the same ground. That earlier presence is also hinted at by the west gable itself, where the lower courses are built with distinctly narrower blocks than the limestone masonry above. Joist holes recorded in 1912 pointed to an unusually large internal loft at the west end, extending east of the doorway to roughly the middle of the church, a feature that would have divided the interior in ways that few comparable structures preserve evidence of.

The church measures just under fourteen metres on its east-west axis and a little over seven metres across, with walls roughly eighty centimetres thick. A plinth is still visible at the base of the south wall and the west gable. The interior is now heavily overgrown, and the north wall's absorption into the boundary infrastructure of the surrounding fields means the ecclesiastical enclosure that once defined the site has been cut through at two points. The field walls have, in a sense, repurposed the old sacred boundary as everyday agricultural fabric, leaving the ruined church sitting quietly at the centre of a landscape that has moved on around it.