The term Manifest Destiny refers to the 19th-century belief in the United States that it was destined to expand across the North American continent. This ideology justified westward expansion and the acquisition of territories, which led to significant events like the Louisiana Purchase and the Mexican-American War. Proponents believed it was a divine right, while critics pointed to its consequences, including the displacement of Native American tribes. Manifest Destiny had profound impacts on U.S. borders, politics, and relationships with other nations throughout the era.