Wedge tombs are the most numerous of Ireland's megalithic tomb types, built during the late Neolithic and into the Bronze Age, and they take their name from their characteristic shape: wider and higher at the western end, tapering as they extend eastward. The example at Scrahallia follows this form faithfully, its gallery running east to west and narrowing to a point roughly one and a half metres beyond the backstone.

The structure measures just over three metres in length, with the broader western end reaching about 1.2 metres across. A transverse slab, now leaning heavily outwards, divides the interior into two distinct sections: a main chamber, roofed by a single capstone, and a smaller portico to the front. The outer walling is closely set and still intact enough to show how the monument once tapered to its eastern close. Traces of the original covering mound also survive around the structure, a detail that is often lost entirely at sites of this age. The description recorded by Cooney in 1986 characterises the monument as well preserved, which, given the general attrition that millennia of Atlantic weather and agricultural activity have visited on similar structures across the west of Ireland, is no small thing.