Somewhere in the pasture fields of Osberstown, a mound that was once considered worth recording on a manuscript map has since vanished from the landscape entirely, or at least from the surface of it. The map in question, held in the National Library of Ireland and compiled sometime between 1727 and 1838, shows a small, steep-sided mound sitting atop a long, gently rising slope with a north-easterly aspect. By the time the Ordnance Survey came to produce its six-inch mapping of the area, the feature was gone from the record. Today, no obvious trace of any artificial mound survives on the ground.

What the mound originally was remains genuinely unknown. Steep-sided artificial mounds in the Irish countryside can represent any number of things: burial monuments, mottes (the earthen platforms associated with early Norman fortifications), or landscape features raised for purposes that are no longer legible. The manuscript map places it firmly enough in the pre-Ordnance Survey world, somewhere in a period stretching across more than a century of cartographic activity, but offers no label or explanation. The absence from the later OS mapping is its own kind of evidence, suggesting the mound had either been levelled, eroded, or was simply overlooked by a later surveyor working to different conventions. The slope it occupied, a quiet north-east facing rise under pasture, is the kind of ground that could absorb a modest earthwork over decades without much fuss.