No ruin marks the spot, no field boundary preserves its outline, and no local tradition seems to have fixed its memory to a particular hill or crossroads. The place itself, Coolatrath, has slipped so thoroughly from the record that the castle's very location remains unknown.

The sole documentary trace comes from the Civil Survey of 1654 to 1656, a vast Cromwellian-era inventory of Irish land and property compiled in the aftermath of the wars of the 1640s. The survey was intended to establish ownership and value across the country, and in the process it captured the names of countless townlands, houses, and structures that might otherwise have left no written record at all. Under the anglicised spelling 'Coolotrath', the survey notes the existence of a castle, nothing more. The entry was identified and published by Robert Simington in 1945, as part of his long-running editorial work on the Civil Survey volumes. Geraldine Stout, who compiled the entry for this site, flags that the castle has not been precisely located, which is a quietly significant admission; it means that no subsequent survey, map, or archaeological investigation has been able to pin it down.

For anyone drawn to the puzzle of it, the search would begin with the townland name itself. Coolatrath lies in County Dublin, and the Civil Survey's record at least confirms that something was standing there in the mid-seventeenth century, substantial enough to be called a castle, a term that in Irish records of this period could apply to anything from a tower house of some pretension to a fortified dwelling of more modest ambition. Tower houses, the most common type of small castle built in late medieval Ireland, were typically rectangular stone towers of three or four storeys, often surrounded by a bawn, a defensive walled enclosure. Whether Coolatrath's castle was of that type, or something else entirely, is not recorded. The land has almost certainly changed around whatever foundations might remain, if any survive at all beneath the surface. This is the kind of site that rewards curiosity about absence as much as presence.