Manifest Destiny was a belief held by many Americans in the 19th century that the United States was destined to expand its territory across the entire continent of North America, from the Atlantic Ocean to the Pacific Ocean. This belief was based on a variety of factors, including the idea that American democracy and capitalism were superior to other forms of government and that it was the duty of the United States to bring these values to the rest of the continent.
The concept of Manifest Destiny can be traced back to the early years of the United States, but it became particularly influential in the 1840s and 1850s, as the country expanded westward and began to acquire new territories, such as Texas, California, and parts of the Southwest.
Manifest Destiny was often used as a justification for territorial expansion and for the displacement of Native American tribes from their ancestral lands. It was also used to justify the Mexican-American War, which resulted in the United States acquiring a large portion of land in the Southwest, including parts of modern-day California, Nevada, Arizona, New Mexico, and Texas.
Despite being a significant force in shaping American history, Manifest Destiny has also been criticized for its role in the mistreatment of Native Americans and for its justification of imperialism and expansionism.