It appears on the 1945 to 1946 revision of the Ordnance Survey six-inch map as a roughly subcircular feature, measuring approximately 26 metres northwest to southeast and 22 metres northeast to southwest. Whether it was a settlement enclosure or simply a field boundary is not recorded, and that ambiguity is now impossible to resolve. The quarry that moved in after the map was drawn has taken the ground with it.

Karstic terrain, shaped by the slow dissolution of limestone bedrock into pavements, sinkholes, and irregular hollows, is a particular feature of this part of Connacht. Such landscapes have a long history of human activity, partly because the thin soils and exposed rock made certain kinds of land use easier, and partly because the natural features of the ground were sometimes incorporated into enclosures and field systems. The Coolagh enclosure was modest in scale, roughly the size of a large back garden, and its purpose was never formally investigated. By the time its existence was noted in any systematic way, it had already been destroyed by quarrying.