In the townland of Barna, Parish of Galbally, in County Limerick, a portal tomb, the type of Neolithic megalithic structure sometimes called a cromlech, once stood some 550 metres from the public road, at the end of the passage leading to a farmhouse. Portal tombs typically consist of two or more upright stones supporting a large capstone, forming a chamber used for burial thousands of years ago. The capstone at Barna was, by one account, large enough to shelter ten men from the rain. It no longer exists.

The tomb appears on Ordnance Survey mapping and was noted by antiquarian William Copeland Borlase, but by the time Lynch wrote up the site in 1910, it had already gone. His correspondent reported that around 1906, the sons of the local farmer blasted the covering stone and used the rubble for field drainage. Lynch's observation that "comment on this act of vandalism is needless" speaks with a restraint that makes it all the more pointed. Earlier destruction had occurred even before that: the Ordnance Survey name book for the 1901 edition records that when a road was made in the area, the cromlech was disturbed and part of it broken up and used for metalling the road surface. The Megalithic Survey of Ireland, compiled by De Valera and Ó Nualláin in 1982, noted that the monument had not been adequately described in earlier survey documents and that its precise nature remained uncertain.

By 1999, a field assessment found no surface remains of the cromlech visible, and the road had since been widened further. The 1940 edition of the Ordnance Survey six-inch map still marks the location with the annotation "Cromlech", positioned immediately north-east of a field boundary, with a farmhouse to the north-west, which gives some bearing for anyone curious enough to visit the area. In the field to the north-east, a possible collapsed standing stone was recorded by the Archaeological Survey of Ireland, measuring roughly 1.2 metres north to south and 0.6 metres east to west, partly buried and orientated north-north-west to south-south-east. A recumbent stone is also visible on satellite orthoimages taken between 2011 and 2013. The pasture holds its secrets at ground level; what remains is more legible from above than from the roadside.