February 1848Primary sourceWell documented
The Treaty of Guadalupe Hidalgo and the Mexican Cession
On the timeline · around February 1848 ·
What happened
The Treaty of Guadalupe Hidalgo ended the Mexican-American War in 1848. Mexico ceded roughly 525,000 square miles — including present-day California, Nevada, Utah, and parts of several other states — and the Rio Grande was fixed as the Texas border, in exchange for $15 million.
Why it matters
The cession completed the United States' expansion to the Pacific, brought a large Mexican and Native population under U.S. rule, and reignited the explosive question of whether the new lands would be slave or free.