"Situation Gargunnock, or Gargownno (as it is called in some old records), is situated about six miles west of the town of Stirling, on the south side of the Forth, by which it is separated from the parishes of Kilmadock, and Kincardine. It is bounded on the east and south, by the parish of St. Ninians, and on the west by Kippen, Balfron, and Fintry.
Name it seems of no great importance, to ascertain the precise meaning of the word Gargownno. Different etymologists will give different explanations of the names of places, in which there is often more imagination than knowledge. Gargownno is probably of Celtic origin; descriptive of the particular spot, on the banks of the Forth, where a small fort stood, of which there is some account in the History of William Wallace. There we read of the Peel of Gargownno, in which an English party was stationed, to watch the passage of the Frew, in its neighbourhood. Wallace with a few followers, took the fort by stratagem in the night, while the English were off guard. The curious stranger may be conducted to the ground which it once occupied; and may perhaps regret, that scarcely a stone is now left to tell the story."
Parish Of Gargunnock (County of Stirling) by Rev. James Robertson (Statistical Account of Scotland 1791-1799)