What was the main reason for the westward expansion of the United States in the 19th century?

The primary driver behind the westward expansion of the United States in the 19th century was the belief in Manifest Destiny. This concept was rooted in the idea that it was the nation's divine right and destiny to expand its territory across the North American continent, from the Atlantic to the Pacific Oceans. This belief motivated settlers and government policies, leading to the acquisition of vast tracts of land as American citizens moved westward in pursuit of new opportunities, resources, and the spread of American ideals.

The enthusiasm surrounding Manifest Destiny also intertwined with notions of American exceptionalism, suggesting that the United States had a unique role to play in the world. This culminated in significant events such as the Louisiana Purchase, the annexation of Texas, and the California Gold Rush, all of which encouraged migration and territorial expansion. By understanding the historical context of Manifest Destiny, we can see that it was a unifying ideology that influenced many aspects of American life and territorial policies during this period, making it the central reason for westward expansion.