The war fought between the United States and Mexico from 1846 to 1848 is known as the Mexican-American War. It stemmed from territorial disputes following the U.S. annexation of Texas, which Mexico considered part of its territory. The conflict was marked by significant battles, including those at Palo Alto, Buena Vista, and the capture of Mexico City. The war ended with the Treaty of Guadalupe Hidalgo, in which Mexico ceded large territories, including present-day California, Arizona, Nevada, New Mexico, Utah, and parts of Colorado and Wyoming, significantly expanding U.S. territory. The war intensified debates over slavery and westward expansion, influencing future U.S. policies.