The only evidence we have of its existence comes from a single historical reference by Smith in 1756, who noted that the castle had been occupied by the Reverend Thomas Connor, cantor of Ardfert. Connor was apparently quite the local scholar; Smith described him as ‘a gentleman well versed in the history and antiquities of his country’, suggesting the castle may have housed an impressive collection of historical knowledge during his tenure.

Today, visitors to the site will find no visible trace of Castle Shannon whatsoever. The structure has been so thoroughly erased by time that archaeologists conducting the North Kerry Archaeological Survey in 1995 could identify nothing more than its approximate location. Whether the castle fell to ruin through abandonment, was deliberately demolished, or simply succumbed to centuries of Irish weather remains unknown.

The complete disappearance of Castle Shannon serves as a reminder of how many pieces of Ireland’s built heritage have been lost without proper documentation. Were it not for Smith’s brief mention in the 18th century, we might never have known a castle stood here at all. The site now exists only as a name on old maps and a footnote in archaeological surveys; a ghost castle that left no stones to tell its story.