Until 1700, the Portage was controlled by the French and their Indian allies. This afforded them power over the fur trade in the territory, then a great commercial activity in the country. By 1763, though, after years of conflict among the French, British and Indian settlers regarding the control of the Portage and the northwest fur trade, France had lost all of its possessions east of the Mississippi River, including governance of the Portage.

The importance of authority over the Portage became evident during the Revolutionary War when a frontiersman, George Rogers Clark, saved the Northwest Territory (now Ohio, Indiana, Illinois, Michigan and Wisconsin) when he defeated the British at Vincennes, Indiana. The Treaty of Paris ended the Revolution and finally gave the United States sovereignty over the region.