Portal Tomb von Knockroe

The portal tomb is oriented east to west. Its capstone lies almost horizontally and is 3.7 m long, 2.7 m wide and up to 0.7 m thick. It lies about 0.7 m above the gravel-covered chamber floor. Of the two portal stones, which have tilted inwards under the weight of the capstone, only one remains beneath it, now at a height of 1.2 m. There are indications of dry-stone walling at the rear.

Beneath the capstone there appear to be markings similar to cup marks, but an excavation would be needed to confirm this. On the upper surface of the capstone is a horseshoe-shaped depression measuring 0.17 × 0.12 m, whose age is uncertain. The southern side shows a spiral motif with a diameter of about 0.4 m.

Portal tombs in Ireland and Britain are megalithic monuments in which two upright stones of equal height, with a door stone between them, form the front of a chamber covered by a capstone. Most portal tombs date from the Neolithic, between 4000 and 3000 BCE, and some were covered by a mound of earth or smaller stones which has since eroded away, leaving the stone skeleton.