d) Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo, signed in 1848, concluded the Mexican-American War and was pivotal in shaping the modern boundaries of the United States. Under this treaty, Mexico ceded a vast territory, including present-day California, Nevada, Utah, Arizona, and parts of Colorado, Wyoming, New Mexico, and Texas, to the U.S. In return, the U.S. paid Mexico $15 million and assumed $3.25 million in debt owed to American citizens. This treaty marked a significant expansion of U.S. territory and had profound implications for Native Americans and Mexican residents in the newly acquired lands.