On May 13, 1846, the U.S. Congress officially declared war on Mexico, initiating the U.S.-Mexican War. This conflict stemmed from the annexation of Texas and the disputes over its border, as well as American desires to acquire lands in what are now California, Nevada, Utah, Arizona, New Mexico, and Colorado. The war significantly altered the map of North America, leading to the Treaty of Guadalupe Hidalgo in 1848, which ceded large territories to the United States and had profound long-term implications for both nations, particularly in shaping regional and cultural identities.
