Nothing is known locally of the true history of Fenit Castle but some fairy tales and and hidden Treasure stories are told about it which appear elsewhere. The Castle is mentioned in King's History of Kerry - as Denny's Castle but a better & truer reference is found in "Hidden Romantic Kerry (T. OSullivan) page 96 ---
"In the State papers relating to Ireland, Sir William Herbert in 1589 complained that pirates were too much favoured in Kerry. "Sir Edward Denny" he added "has received Gascon wine which was robbed from Frenchmen, and Lady Denny has received goods which were taken from Buttaines[?]. One, Captain Marss [?] of Youghal, a known negotiator in these kinds of affairs, is shortly to remove to Tawlaght, a castle of Sir Edward Denny's, near Tralee, there to exercise that Trade".
The castle is not situated in Taulaght, which is the next townland but in the townland of Fenit Without, and this version quoted above conforms to local tradition hereabout that the Castle was a protection post for Customs duties while it winked according to the fashion of the times at a lucrative trade in smuggling with France and Spain.