How did American Indians react to white settlers in the Northwest Territory?

They didn't like it because they wanted their lands for the gold that was underneath and killed off their food source as a result they were angry and wanted to fight

Settlers from New France entered the region in 1634, ultimately forcing the nation to encounter tribes that have lived in the territories for hundreds of years. Settlers, cattle ranchers, explorers, and fur traders pushed the natives from their homelands, resulting in a series of wars between tribes and the federal government. At first, the federal government's policy to deal with these tribes was brutal, and protesting by the tribes resulted in destruction of their land and force-removal by government. Because the tribes depended on buffalo for almost everything they needed, they fought to protect their hunting lands from the white men, including trying to destroy wagon trains carryign settlers to California from Oregon. The Santee Sioux, a tribe that lived along the northeastern edge of the great plains, signed treaties with the government to give up ninety percent of their land. In exchange, the United States agreed to make yearly payments to the tribe in order for them to buy food and other necessities from white traders. However, in 1862, the government was late with yearly payment. As a result, the tribe lacked money to buy food, and white traders refused to give them food, one trader going so far as saying "if they are hungry, let them eat grass." This hunger led to anger, and the local chief gave orders for war.

Ultimately, the tribes residing in the Northwest Territory fought for their lives and their culture against white settlers and a government that treated them like animals and stole their lands. This maltreatment treatment, quite obviously, made the tribes angry enough to go to war to protect themselves.