The Portal Tomb of Cleenrah (also known as Cleenrah Cromlech or Cleenrah Dolmen, and sometimes spelled as Cleenrath) is located approximately 200 meters north of Lough Leebean and 1.0 kilometer west of Lough Gowna, northwest of Granard, and about 1.2 kilometers from the Portal Tomb of Aughnacliff in the townland of Cleenrah (in Irish, Claonráth, meaning “the sloping fort”) in County Longford, Ireland. Portal Tombs are megalithic structures built between 4000 and 2500 BC during the Neolithic period across the British Isles. They are characterized by two equally tall, upright stones with a door stone in between, forming the front of a chamber covered by a partially massive capstone.

The Portal Tomb of Cleenrah is a well-preserved west-east oriented megalithic structure. It consists of two portal stones, two side stones, an end stone, and a capstone. The northern portal stone stands at approximately 1.7 meters in height, 1.1 meters in width, and 0.65 meters in thickness. The southern portal stone measures around 1.35 meters in height, 0.95 meters in width, and 0.7 meters in thickness. The gap between the portal stones is 0.5 meters wide. The two side stones are tilted outward and lie within the line of the portal stones. The northern side stone is about 1.9 meters in height, 2.15 meters in length, and 0.75 meters in thickness. The southern side stone is also approximately 1.9 meters in height, 2.2 meters in length, and 0.7 meters in thickness. The eastern end stone is around 1.5 meters in height, 1.0 meter in width, and 0.3 meters in thickness. As it does not completely close the chamber, a smaller stone measuring 0.55 meters × 0.4 meters × 0.2 meters fills the gap. The capstone, which rests on both portal stones and the end stone, is approximately 2.7 meters in length, 2.5 meters in width, and 1.25 meters in thickness. The overall length of the Portal Tomb is 2.75 meters, but the chamber interior, between the portal stones and the end stone, is only 1.6 meters long.