From Historical Rutland : an illustrated history of Rutland, Vermont, from the granting of the charter in 1761 to 1911 by Rev. F. E. Davison, Rutland, Vt.: P.H. Brehmer, 1911, page 4:
First Settlement of County
The principal towns in Rutland County were chartered in 1761. But the time of the first settlement is a matter only of conjecture. It is certain that a brisk trade had been carried on between Canada and Massachusetts before any white man had settled in this territory, and that business was transacted and goods transported into Canada, and that the line of travel was directly across what is now the county of Rutland. There is a journal still in existence of a trader who made the journey from Massachusetts to Crown Point, N. Y., in 1730 in which he writes in glowing terms of the richness of the soil along Otter Creek.
But when the French War terminated in the surrender of the province to the north to Great Britain, many of the soldiers who had crossed Vermont on their warlike expeditions, decided to settle within its limits, and Governor Wentworth, the colonial governor of New Hampshire, received numerous applications for charters, and in 1761, the principal towns now included in Rutland, Bennington and Addison counties were chartered.