Manifest Destiny: The belief held by many Americans in the 19th century that it was their destiny and right to expand westward across the continent.
Treaty of Guadalupe Hidalgo: The peace treaty signed between the United States and Mexico in 1848, which ended the war and ceded a significant amount of territory to the United States.
Mexican Cession: The name given to the vast territory that Mexico had to cede to the United States as part of the Treaty of Guadalupe Hidalgo, including present-day California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado and Wyoming.