It appeared on the first edition Ordnance Survey six-inch map under the name Raheen, a diminutive Irish place name meaning little fort or small ringfort, and then, as subsequent map editions were produced, it simply disappeared from the record. No later OS edition marked it at all. That kind of cartographic vanishing act is unusual enough to prompt curiosity, and the site has, over the decades, rewarded closer attention.

A ringfort is a roughly circular enclosure, typically defined by one or more earthen banks and ditches, built during the early medieval period in Ireland as a farmstead or settlement. Most have a single enclosing bank, so the discovery at Baldonnell Little is particularly interesting. When a field inspection was carried out in 1986, surveyors found a raised circular area with an internal diameter of thirty-three metres, defined by a low bank surviving to about 0.3 metres in height along the south-east to west arc, with traces of an external fosse, or ditch, ranging between seven and thirteen metres in width. A possible entrance was identified in the north-east sector. That much was already suggestive of something more complex than an ordinary single-bank enclosure. Then, in 2011, a review of LiDAR data, a remote sensing technique that uses laser pulses to detect subtle variations in ground surface, revealed that the remains were those of a tri-vallate enclosure, meaning it originally had three concentric banks and ditches. Tri-vallate ringforts are comparatively rare in the Irish landscape, and their presence is often associated with higher-status settlement. A geophysical survey followed in 2013, though the results were described as limited. The site is referenced in work by Ua Broin from 1944 and by Healy in 1974, and was compiled into the national record by Geraldine Stout and Paul Walsh.

The site sits on flat agricultural land near Baldonnell, an area most people associate with Casement Aerodrome rather than early medieval archaeology. There is no formal public access or signage, and the earthworks are low and unspectacular to the untrained eye; the bank barely rises above the surrounding ground. The value here is less in dramatic visual impact and more in understanding that even in heavily managed, suburban-fringe landscapes, early medieval enclosures can persist almost invisibly beneath the fields, waiting for the right technology to reveal what centuries of ploughing and cartographic neglect had effectively erased.