At Vincennes, he started up the Wabash River with the expectation of adding to his force from the Canadian villages of Ouiatenon (present day West Lafayette, Indiana) and Kekionga (present day Fort Wayne). La Balme apparently expected Canadian residents at Fort Detroit to join him once they arrived. La Balme kept the French ambassador, Anne-César de La Luzerne, updated on his movements, and the expedition marched under a French flag.
In 1780, allegedly under secret orders from General Washington, but as likely acting on his own, La Balme traveled down the Ohio River to Kaskaskia. The success of General Clark's capture of Fort Sackville at Vincennes inspired La Balme to attempt a similar feat against the British at Fort Detroit. La Balme arrived in Kaskaskia as a French officer and was "greeted as Masiah" by the local Canadien residents, who had been living under British rule for over a decade.