The Mexican-American War, which began on May 13, 1846, was a significant conflict driven by the United States' desire to expand its territory. The U.S. aimed to acquire and settle land in Mexico's southeastern regions, which were sparsely populated at the time. This war was rooted in complex issues, including territorial disputes and a belief in Manifest Destiny—the idea that Americans were destined to expand across the continent. The conflict had profound implications for both nations, leading to significant territorial changes following the war's conclusion. The U.S. victory resulted in Mexico ceding large territories, including present-day California, Arizona, New Mexico, and Texas. This expansion intensified debates over slavery and statehood in the United States, impacting the nation’s political landscape. The war continues to be a point of reflection regarding U.S.-Mexico relations and the historical context of territorial expansion in North America. Understanding this period is essential for grasping the historical narrative that shapes contemporary discussions about borders, identity, and cultural heritage in both countries.