This one, in the upland Coillte forestry at Brisha in County Laois, is remarkable for what it may or may not contain at all. Classified as a possible enclosure, an enclosure being a broadly defined term for a defined area bounded by a bank, ditch, or wall, often of prehistoric or early medieval origin, it never made it onto any edition of the Ordnance Survey six-inch maps. Its entire claim to existence rests on a single aerial photograph taken by the Irish Air Corps around 1950.

Aerial photography has long been one of archaeology's more quietly dramatic tools. Cropmarks, soil discolouration, and subtle changes in ground level that are invisible from the surface can reveal themselves clearly from above, and the Irish Air Corps Aerial Photograph collection has been a useful source for identifying sites that ground survey alone would miss. In this case, however, the photograph seems to have been the beginning and end of the evidence. When a site inspection was carried out in July 2018 by Ed Lyne, no surface remains could be found in the area indicated. The enclosure, if it ever existed as a physical structure, has left nothing behind that a person walking through the forestry could identify.