Supposedly, MacDougall met the Scottish king Alexander II circa 1249 and "refused a demand for Cairburngmore and three other castles" so it is possible that Iselborgh was one of them.

[3] In a 1495 confirmation of a 1390 charter, John of Islay's son Donald granted "command and possession of the castles of Kernaborg and Isleborg together with small Floda and Lunga" to Lachlan Lùbanach Maclean of Duart.

[3] An unusual feature of the Cairnburgh Castle its that its defences straddle both the island of Cairn na Burgh Mòr itself and its smaller companion isle.

[11] There was certainly a substantial fortification at this location on Tiree, the Old Statistical Account of the late 18th century referring to castle with a drawbridge there at some point in the past.

[15][16] There is a reference to the "Inch of Teinlipeil" (probably the "island of Hilibol") in relation to the death of Sir Donald Galda MacDonald of Lochalsh in 1519[17][b] but otherwise the castle's name is unrecorded.

Munro, writing in 1973, suggested that there was not "sufficient evidence that Isleborg 'certainly' lay in the Treshnish group, as Kernaborg undoubtedly does; why should there be two castles there?...