This period of history—around the 1830s—is a period of many removals, and it is important to approach it as such in order to contextualize the rest of history occurring in the United States at that time. Without recognizing that, westward expansion is less iniquitous and more romantic, and manifest destiny is not as abhorrent as it was just another policy that the United States was following. The people primarily affected by these removals were Native peoples living in the Southeast and Eastern United States, and in particular, the tribes sometimes referred to (in an incredibly racist manner) as the five “civilized” tribes, which consisted of the Cherokee, Chickasaw, Seminole, Muscogee, and Choctaw peoples. These tribes were not at all the only groups affected, but are the most publicized of the removals. These peoples were moved to “Indian Territory,” in what is now Oklahoma from their lands that spanned Georgia, the Carolinas, Florida, Mississippi, Tennessee, Arkansas, Louisiana, etc.
Historical issues such as the extension of slavery into Western territories and the removal of Native communities are interdependent processes—there really isn’t any other way to see it. One of the greatest factors behind the removal of Native communities from the Southeast was the desire to move white settlers into the land to expand the institution of slavery, especially as abolitionism was starting to garner more support in the Northern states—as everything, obviously, leads toward the civil war. Alongside that, many of the Native communities that were moving westward to Indian Territory had adopted slavery as an institution and did not sacrifice that as they made the journey out west. Policies regarding Native Americans were changing significantly during this time period, especially because of the Marshall trilogy of Supreme Court cases, starting with Johnson v. McIntosh, which established that Native Americans did not have the right to sell their own land, followed by Cherokee Nation v. Georgia, which established that Native nations were domestic, dependent nations, and then finished with Worcester v. Georgia, which established that the Cherokee nation is a sovereign nation occupying its own territory—and, therefore, Georgia’s laws had no force over it.