What acquisition gave the US its present southwest and reignited the slavery issue with the discovery of gold in California in 1848?

The acquisition that gave the U.S. its present southwest was the Treaty of Guadalupe Hidalgo, which ended the Mexican-American War in 1848. This treaty resulted in the U.S. gaining territories that include present-day California, Arizona, New Mexico, Nevada, Utah, and parts of Colorado and Wyoming. The discovery of gold in California the same year intensified the debate over slavery as new territories were admitted to the Union, reigniting tensions between free and slave states. This ultimately contributed to the growing divisions that would lead to the Civil War.