Not visible to anyone walking the field, and only faintly suggested from above, a possible earthwork at Coolalough has been known to archaeologists for nearly four decades, yet remains unexcavated and essentially unconfirmed. Its existence depends entirely on what the land reveals from altitude, and even that evidence is ambiguous.

The site first came to attention during the Bruff aerial photographic survey of 1986, which catalogued it as Bruff 69 (reference AP 5/2075). Aerial surveys of this kind are a standard archaeological prospecting method: differences in soil moisture, crop growth, and vegetation stress can betray buried features, including ditches, foundations, or banks that are otherwise invisible at ground level. These are known as cropmarks, and they form when buried archaeology affects how plants above them grow, producing subtle variations in colour or height that only become apparent from the air. The Coolalough feature appeared to suggest a rectangular outline, a shape associated with any number of past uses, from enclosures to field systems to settlement remains. Decades later, a Digital Globe orthoimage taken between 2011 and 2013 showed a faint cropmark in approximately the same location. A more recent Google Earth image from September 2020, however, revealed an irregular-shaped area that may simply be a natural pond. The record was compiled by Fiona Rooney and uploaded in June 2021.

The site sits in pasture, positioned 23 metres west of the townland boundary with Knockainey West and 20 metres north of the boundary with Rathanny. There is no public access point specifically associated with it, and nothing on the ground would signal its presence to a passing visitor. Anyone with a serious interest in the site would do better to begin with the aerial and satellite imagery referenced in the record rather than attempting a field visit. The honest conclusion at this stage is that no one knows with certainty what lies here, and that uncertainty is itself part of what makes a site like this worth noting.