This one sits in a small copse on low-lying, damp ground about 600 metres east of the River Shannon, at the edge of an extensive tract of bog that has almost certainly helped preserve it, however imperfectly, for several thousand years. Wedge tombs are the most numerous type of megalithic tomb in Ireland, built during the late Neolithic and into the early Bronze Age, generally characterised by a gallery that is wider and higher at one end, with that broader end typically facing west. The Clooneen example follows this orientation, its gallery aligned east to west and measuring approximately 8.5 metres in length.

The internal arrangement, though considerably disturbed, is still legible to a careful eye. A septal stone, a dividing slab set across the width of the gallery, separates a short portico at the western end from the main chamber to the east. Two façade stones stand slightly forward of the northern end of the septal stone, flanking what would have been the formal entrance to the portico, and a transversely set stone sits just west of the southern end of the same dividing slab. Several sidestones, the upright slabs that once formed the long walls of the gallery, have fallen or shifted from their original positions, and three or possibly four roofstones, all dislodged to varying degrees, now lie across the eastern portion of the chamber, partly obscuring the sidestones beneath them. A possible outer wall stone survives near the western end of the chamber, and the whole structure rests within a mound of roughly oval outline, the earthen cairn material that would originally have covered and supported the entire monument.

The setting itself adds a layer of strangeness to any visit. The copse stands on ground that is noticeably wet underfoot, hemmed in by bog, and the displaced stones give the monument a collapsed, almost secretive quality, as though it has been slowly pulling itself into the earth. The roofstones lying athwart the gallery, rather than sitting flush above it, are the most visually striking feature, and they offer an accidental cross-section of how the structure was once assembled.