He was also to learn, if possible, how far the boundaries of Canada extended towards the Mississippi, and the number of French posts, settlements, and inhabitants along that river.
Sir William left his home at Fort Johnson on the Mohawk river early in July 1761.

Scarcely had he begun his journey when he was warned that it was dangerous to proceed, as the nations in the west were unfriendly and would surely fall upon his party.

But Johnson was confident that his presence among them would put a stop to 'any such wicked design.' As he advanced up Lake Ontario the alarming reports continued.

The Senecas, who had already stolen horses from the whites and taken prisoners, had been sending ambassadors abroad, endeavouring to induce the other nations to attack the British.

Johnson learned, too, that the Indians were being cheated in trade by British traders; that at several posts they had been roughly handled, very often without cause; that their women were taken from them by violence; and that they were hindered from hunting and fishing on their own grounds near the posts, even what they did catch or kill being taken from them.