That ambiguity is, in its own quiet way, the most interesting thing about this entry in the record of protected monuments. The site appears on the Westmeath Record of Monuments and Places, yet no physical trace of any structure has ever been captured on aerial imagery, and no paper archive exists to explain what was once thought to be here.

The monument was first catalogued in 1985, described cautiously as a "Tower (site of)", that parenthetical qualifier doing a great deal of work. By 1996, the designation had been quietly upgraded to simply "Tower", dropping the hedging language even as the evidence for any such structure remained elusive. It does not appear on the first edition Ordnance Survey six-inch maps, which date from the mid-nineteenth century and are generally reliable for recording even modest built features in the landscape, nor on any later edition. Digital Globe satellite imagery taken between 2011 and 2013 confirmed that no surface remains are visible within the relevant part of the demesne. Ballynagall demesne is a wooded estate landscape, and tree cover can certainly obscure low earthworks or buried stonework, but the absence of any corroborating cartographic evidence leaves the tower in a state of considerable uncertainty.

What persists, then, is a name on a map and a category without a structure. It is a reminder that heritage inventories sometimes preserve the memory of something that has vanished entirely, or possibly the memory of a misidentification passed forward through successive surveys. The tower at Ballynagall may have stood and fallen without ever being properly recorded, or it may never have stood at all.