The Treaty of Guadalupe Hidalgo, signed in 1848, ended the Mexican-American War and had significant repercussions for both nations. The agreement resulted in the U.S. acquiring about 525,000 square miles of territory, including present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico. This territorial gain fulfilled the United States' manifest destiny ideology, fueling debates over slavery's expansion into new territories. The treaty also prompted tensions between Mexico and the U.S., as it represented a dramatic shift in power and land ownership, and it contributed to the ongoing struggles of Mexican Americans and Indigenous peoples in the newly acquired territories.