Historical1848
Treaty of Guadalupe Hidalgo Signed
The United States and Mexico signed the Treaty of Guadalupe Hidalgo, ending the Mexican-American War. Mexico ceded vast territories including present-day California, Nevada, Utah, and parts of Arizona, New Mexico, Colorado, and Wyoming to the United States.
Why It Matters
This treaty dramatically expanded the nation's territory and intensified the debate over whether slavery would be allowed in the new lands, accelerating the sectional crisis that led to the Civil War.