What was the outcome of the Mexican-American War for the United States?

The outcome of the Mexican-American War, which lasted from 1846 to 1848, was significant for the United States primarily because it acquired vast territories in the west. Following the war, the Treaty of Guadalupe Hidalgo was signed, resulting in the U.S. gaining approximately 500,000 square miles of territory. This acquisition included present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico.

The significant territorial gains spurred westward expansion, which was rooted in the belief of Manifest Destiny—the idea that Americans were destined to expand across the continent. These new lands contributed to the growing economy and provided opportunities for settlement and development.

While the treaty helped establish a form of peace after the conflict, its primary legacy was the territorial expansion of the United States, shaping the nation's future by increasing its size significantly and catalyzing debates over slavery in the new territories. The other options address topics like peace treaties or policies regarding Native Americans, but they do not encapsulate the transformative impact of the territorial gains resulting from the war. Additionally, California did not gain immediate statehood post-war; it became a state much later in 1850 following the influx of settlers during the Gold Rush.