What survives today is fragmentary: a faint arc of raised ground to the north-east, a scarp, a drain, and the chord of what was once a much larger enclosure. A farm track now cuts across it, and the field boundaries have long since reshaped the space. It is the kind of site that rewards patience and a good eye for slight changes in ground level.

The Ordnance Survey's six-inch map of 1834 still shows it clearly, rendered in the gothic lettering that surveyors reserved for antiquities and labelled simply as a fort. In Irish archaeological usage, a fort of this type generally refers to a ringfort, a circular embanked enclosure typically dating from the early medieval period, between roughly the fifth and twelfth centuries, and most often associated with a single farmstead or a high-status household. The Coolmannan example, with its external diameter of around 65 metres, would have been a substantial one. By the 1907 edition of the same map series, the site had already been redrawn as a subrectangular field measuring approximately 35 metres on each axis, with the distinctive circular form largely lost to agricultural reworking. A farm lane had been driven through its northern interior, and the perimeter bushes that were still visible in 1834 had become the edges of an ordinary field. What the two maps together record is not just a site, but the pace at which a significant earthwork can be reclassified from antiquity to farmland within the span of a single lifetime.