The American Frontier refers to the period of westward expansion in the United States during the 19th century, characterized by the exploration and settlement of lands west of the Mississippi River. This era was marked by significant cultural, economic, and political developments, shaping the national identity and leading to the displacement of Native American tribes.
American Expansionism refers to the period in U.S. history where the nation sought to expand its territory and influence across the North American continent and beyond, driven by a belief in manifest destiny and the desire for economic growth. This ideology justified the displacement of Native American tribes, the Mexican-American War, and the acquisition of territories such as Texas, California, and Alaska, shaping the geopolitical landscape of the United States.