Which was a consequence of western expansion that affected American Indians in the mid 1800s

They were forced out of their homelands to newer territories.

There were a considerable number of consequences that occurred to the American Indian as a result of westward expansion. For one, the white settlers brought diseases that the Indians were not immune to, such as smallpox, and caused an epidemic of disease which killed more than half of to be population. Also, white expansion caused the almost extinction of the American buffalo which the plains Indians depended on for survival because e bison were hunted for sport and left to rot on the prairie whereas the Indians used every part of the buffalo.