This is a wedge tomb, one of the most common megalithic tomb types in Ireland, built by farming communities during the late Neolithic and into the Bronze Age, roughly between 2500 and 2000 BC. The form is distinctive: a long, wedge-shaped gallery that tapers from a wide western entrance toward a narrower eastern end, and it is this western facade that still reads most clearly here at Gorteendarragh.

The structure at the western end preserves considerable detail. A large main chamber, measuring 4.8 metres in length, is divided from a front portico by a septal stone, a thin upright slab that separates the burial space from the entrance area, standing just over a metre high. The portico itself, roughly 1.8 metres east to west and up to 1.5 metres across, is flanked by façade-stones, the formal architectural face of the monument as its builders intended it to be seen. Behind all of this lies a long earth and stone bank, 15 metres in length and 4 metres wide, running east to west. At the bank's far eastern end, two upright stones hint at the possibility of a second chamber, though this remains uncertain. About 30 metres to the north, a further possible megalithic structure has been recorded, raising the question of whether this part of the Leitrim landscape once held a loose cluster of monuments rather than a single isolated tomb. The site was examined and described by Ruaidhrí de Valera and Seán Ó Nualláin in their 1972 survey of megalithic tombs, which remains a foundational reference for this class of monument across the Irish midlands and west.