While the congress debated the fate of western land claims, battles continued in the Ohio and Mississippi River valleys. The British commander at Fort Michilimackinac on Lake Huron recruited Sioux, Chippewa, and Sauk warriors to attack Spanish forces along the Mississippi, while soldiers at Fort Detroit armed Ottawa, Fox, and Miami warriors to assault American settlers flooding into the Ohio River valley. British forces also moved deeper into this region, establishing a post at Vincennes on the Wabash River.

The response to these British forays was effective, if not well coordinated. In 1778 a patriot surveyor, George Rogers Clark of Virginia, organized an expedition to counter Indian raids in the West and to reinforce Spanish and French allies in the upper Mississippi valley. He fought successfully against British and Indian forces at Kaskaskia and Cahokia on the Mississippi River. Then Clark launched a surprise attack on British forces at Vincennes. Although Detroit remained in British hands, Spanish troops defeated British-allied Indian forces at St. Louis, giving the patriots greater control in the Ohio River valley (Map 6.2).

In the summer of 1779, colonial General John Sullivan led a campaign to wipe out Mohawk, Seneca, Cayuga, and Onondaga villages in central and western New York. He succeeded in ending most attacks by Britain’s Iroquois allies and disrupting the supplies being sent by British forces at Fort Niagara. Patriot attacks in Ohio also continued. In one of the worst atrocities fomented by patriots, Pennsylvania militiamen massacred more than one hundred Delaware men, women, and children near present-day Canton, Ohio.

Battles between Indian nations and American settlers did not end with the American Revolution. For the moment, however, the patriots and their allies had defeated British and Indian efforts to control the Mississippi and Ohio River valleys.