The Treaty of Guadalupe Hidalgo was signed on February 2, 1848, ending the Mexican-American War and marking a significant moment in U.S. history as it resulted in the U.S. acquisition of vast territories. This treaty ceded approximately half of Mexico’s land, including present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico, which played a pivotal role in the westward expansion of the United States and had lasting impacts on Native American communities.