On the island of Inishmurray, off the Sligo coast, one such structure sits tucked into the curve of a monastic enclosure wall, reached by a narrow sunken passage that angles down through steps into a low doorway. Traditionally called Trahanacorresh, it is a clochan, the drystone beehive-roofed cell type associated with early Irish monasticism, but this one is more spatially complex than the form usually suggests.

The building occupies the north-east arc of the Cashel, the great stone enclosure that defines the ecclesiastical core of Inishmurray. A corbelled roof, built by laying overlapping stone slabs in ever-tightening courses until they meet at the top, covers the principal chamber. From there, a low creepway, the kind of doorway through which a person must stoop or crawl, leads south into a smaller chamber, and above that a second small chamber is tucked beneath the corbelled roof, reached through an opening cut into the slabbed ceiling of the lower one. On the exterior, a broad scarcement, a projecting ledge or shelf built into the stonework, runs around the building at roughly shoulder height, though it is irregular: along the north-east face it is effectively formed by the surface of the Cashel wall itself, and it disappears entirely on the west front where the doorway is. The approach passage adds its own oddity, with a small arrangement of slabs and rubble forming what appears to be a bay or stall set into one side. The survey published by J. O'Sullivan and T. Ó Carragáin in 2008, drawing on fieldwork carried out between 1997 and 2000, provides the detailed record on which any understanding of this structure now rests.

Inishmurray is an uninhabited island, and reaching Trahanacorresh requires first getting to the island itself, typically by arrangement with boat operators from the Sligo or Donegal Bay coastline. Once within the Cashel, the clochan sits immediately beside the north-east entrance, so it is encountered early. The descent into the passage gives a sense, even before the doorway, of how deliberately inward and compressed this architecture is.