Complex sentence: In 1789, Kinzie lost his business in the Kekionga (modern Fort Wayne, Indiana) and had to move further from the U.S. frontier, as the US excluded Canadians from trade with the Native Americans in their territory.
Split into simpler sentences: In 1789, Kinzie lost his business in the Kekionga (modern Fort Wayne, Indiana) and had to move further from the U.S. frontier. The US was excluding Canadians from trade with the Native Americans in their territory.