Portal tombs represent a third category of Neolithic monuments. The entrance of a portal tomb is marked by tall portal stones. On top lies a huge single cap stone resting on the portal stones on the front and sloping at the rear where it rests on the backstone.
They are usually found on their own in an isolated location
The Labby Rock is located on the ridge of Moytura on the east side of Lough Arrow and is located on private land and can not be accessed. This area has a fine selection of megalithic monuments, at least 14 have been recorded by the megalithic survey.
Labby rock is one of the largest dolmens in Ireland, it has a capstone weighing an estimated 70 tons. It is found in the valley just north of the highest part of the ridge of Moytura.