Final answer:
The Treaty of Guadalupe Hidalgo, signed in 1848, resulted in Mexico ceding territories that became California, New Mexico, Arizona, Nevada, Utah, and parts of Colorado and Wyoming to the U.S., increasing the U.S. territory by 525,000 square miles.
Step-by-step explanation:
The Treaty of Guadalupe Hidalgo signed in 1848 following the Mexican-American War, resulted in a significant change in the political landscape of North America. Mexico ceded substantial territories to the United States, comprised of the present-day states of California, New Mexico, Arizona, Nevada, Utah, and portions of Colorado and Wyoming. This land acquisition, known as the Mexican Cession, represented a roughly 55% increase in the territorial size of the United States during that era and played a crucial role in the fulfillment of Manifest Destiny.
The treaty not only increased U.S. territory by approximately 525,000 square miles but also set the stage for future conflicts and issues regarding land rights and citizenship for newly annexed populations. Additionally, it set the Rio Grande as the southern border for Texas and established agreements regarding the assumption of debts and payment for the land ceded.